Charmed LifeEditHalliwell Manor and reawakened the Power of Three, Phoebe had a Premonition of two children getting hit by a car, Phoebe intervened and wound up in the hospital due to saving two kids from getting hit by the car. She explains to Prue their magical heritage, but she is completely dismissive of the discovery until she accidentally moves a cup of cream across the bar. Distraught by the new information, she continues to argue with Phoebe about their heritage and about using her powers. Phoebe discovers anger to be the trigger to her telekinesis and endlessly discusses the issues that she has. First with Roger, then their father Victor and eventually Phoebe herself. This causes her anger to escalate to a maximum point and subsequently removes everything in a section of a pharmacy that they're in. After letting out the repressed anger, she finally begins to accept her identity as a witch.
She continues to retain a normal life while taking the lead for the Charmed Ones in fighting evil. However, her magical life greatly interferes with her romantic one. She reunites with high school flame, Andy Trudeau who is an inspector of the San Francisco Police Department who works on supernatural phenomenon, and though she loves him, her secret creates a great gap in their relationship and Prue eventually ends their relationship after realizing it wouldn't have worked out even if she told him that she was a witch. Prue came to the realization after casting a Truth Spell to learn how Andy would react to her being a witch. Andy was at first surprised, but said eventually he would be able to deal with it, he just couldn't deal with the fact Prue lied to him.
Various demons attack the Charmed One's in an attempt to acquire Prue's power, most notably Whitaker Berman, a demon of Fear known as Barbas and Gabriel Statler, a Lord of War. Whitaker Berman was a wheelchair bound scientist who discovered a way to leap in to dreams, a power known as Dream Leaping. Whitaker targeted several women, his last being Prue. While taking a bath, Prue fell asleep and Whitaker appeared in her dream, scratching her back with a sponge. Prue believed it was only a dream until she looked into a mirror and saw the scratch marks on her back. Whitaker attacked her again, this time trying to persuade her to jump off a building to her death. Prue was able to overcome Whitaker and she killed him in the dream.
Prue also became the target of Gabriel Statler, who was encountered centuries prior by a Halliwell ancestor, Brianna Bowen. Gabriel's sister Helena poses as an antique seller at Buckland Auction House seeking Prue's expertise on various pieces the Statler family has stored in a warehouse and asks her to come by, where she is then attacked by Gabriel. After locating an entry on Gabriel and his crystal sword, Prue casts a Charm of Multiplicity, after which two more Prues are created, hoping they will be strong enough to get Gabriel's sword away from him like Brianna did centuries ago.Also, by becoming witches, she and Phoebe's relationship improves greatly throughout the season, turning from two rivaling sisters closer to each other than when they don't know about their heritage, along with Piper. Prue was also reluctant about the idea of becoming a mother due to her tragic childhood and magical life, but after a young witch named Max sends a message (with assistance from Leo), she learns from the boy's experience and realizes that she does want to have children.
While trying to protect a young child from the Grimlocks, she finds out that her telekinesis had escalated from channeling through squinting her eyes to moving her hands, making her a powerful weapon in following seasons, but this encounter with the Grimlocks eventually leads to her ex, Andy, finding out about her secret when she saves him from one of them. When Phoebe comes into contact with an evil spirit named Jackson Ward, Andy helps them by locating a weapon used by Jackson and Prue shares the Book of Shadows with him and how she cast a Truth Spell to learn if he would accept her secret. Although Andy is at first upset, he accepts what Prue did and the two remain close.
Andy protects the Halliwell's secret with all his life, and his and Prue's feelings started rekindling but even her powers weren't enough to save him when he was killed by the demon Rodriguez in the season finale. When Rodriguez attacked at the Manor, Andy ran in and was struck by an energy ball; dying upon impact. Prue was left unconscious and had a vision of Andy, Andy told her that she needs to wake up and continue doing what she does and that he will always love her. Prue then attends Andy's funeral with her two sisters and Darryl Morris, placing a rose upon his coffin.
- "That's right, Phoebe, isn't it? The oldest sister, always supposed to be able to figure things out? Well, if that's the case, then how come i couldn't save Andy? If i'm supposed to be so powerful, then how come i couldn't save him? I mean, my god, don't you understand? Andy died because of me, it doesn't matter what he said, it was my fault. How could it be good to be witches if all it does is get the people we love killed?"
- —Prue blames her self for Andy's death at the hands of Rodriguez[src]
At the beginning of the season, Prue blamed herself for Andy's death and when a demon known as Abraxas attacked and stole the Book of Shadows, she was unable to use her powers. Abraxas then sent the warlock Nicholas after Prue at her place of work, he attacked her but just before collapsing she chanted the spell to destroy him. She landed up in the hospital where her sisters met her, she told them she felt that Abraxas taking the Book was a way out for them; they could go back to leading normal lives again which meant not risking their lives all the time and losing the ones that they love.
Prue then seeks solace in Darryl Morris, Andy's partner at the police department. Darryl told Prue that he wanted him to give her a message from him. That morning, after he saw her, Andy told him to tell her that if anything were to happen to him, that it wouldn’t be her fault. He didn’t want her to blame herself. She and her sisters then tried to go up against Abraxas again, but Prue was unable to channel her powers and get the Book. She then shared her feeling for feeling like she was to blame for Andy's death. Piper and Phoebe comforted her and afterwards, she was able to go up against Abraxas with her sisters and reclaim the Book of Shadows.
Prue and her sisters traveled to 2009 after Phoebe had a premonition of being burned alive. In 2009, Prue was a blonde and owned Buckland Auction House in San Francisco as well as 3 more in London, Tokyo and Paris. Prue had magical troubles, even with non-magical beings. Her telekinetic powers developed, giving her the new ability of Astral Projection, allowing her to project her mind and consciousness into a tangible state.
Aside from her powers, her maturity also evolves as she decides to quit her job at Buckland's to figure out what she really wanted, eventually pursued her childhood dream of becoming a photo journalist. She was kidnapped by former gangster Bane Jessup, to help him fend off against the Ordo Malorum. Though she was completely dismissive of protecting him, he sacrifices himself to protect when a demon attacks. She manages to chase him away, however, and Bane wins her trust. After this, they begin to fall in love, and Prue agrees to help him vanquish Litvak in exchange for him to return to jail, which he agrees as well.
Prue also casts her first makeshift spell - a Good Luck spell to remove the bad luck bestowed upon a woman, Maggie Murphy, by a Spirit Killer. The Spirit Killer than targets Prue implanting thoughts of doubt, fear, blame and depression in her mind in an attempt to try to get her to commit suicide by jumping off of a bridge. The Killer causes her to be fired from her new job at 415 Magazine, but Prue is able to overcome the Killer's telepathic suggestion and he is then destroyed forthwith. She regains her job at 415 by taking an impeccable photo of Maggie.
As the sister most traumatized by the death of their mother, Prue has had problems not only with water, but also with facing the dock where she drowned. She finds out later that her mother was killed by a Water Demon and that her former whitelighter, Sam Wilder; the father of their long-lost half-sister, Paige, had been waiting for them to come, to sacrifice anyone to protect her and her sisters from facing the demon, going to the limit of erasing their memories. Once they remember again, Prue confronts him for sitting on the sidelines and watching people die, and convinces him to help. Piper and Leo find out that Sam and Patty were in love once upon a time. When they realize what Patty had planned to do to vanquish the demon, Prue and Sam decide to confront it together. Sam subsequently sacrifices himself to protect Prue.
While the sisters go up against Four Horsemen of the Apocalypse, they inadvertently cast the wrong spell sending Prue to the Astral Plane along with War; this forces the sisters to work together with the remaining three Horsemen in order to get their prospective counterparts back to the physical world. Prue is successfully returned to our world and the Source of All Evil vanquishes the Horsemen for failing.
After the Infernal Council is unimpressed with all the demons failing to destroy the Charmed Ones, tipping the scales from Evil to Good, they send a Dragon Warlock and a Genie after the Halliwells in an attempt to destroy them once and for all. The Genie tricks Prue into making a wish causing her to become seventeen again, rendering her powerless and vulnerable to the Dragon's manner of evil. Prue then sneaks out of the Manor and runs into the Dragon while driving down a San Francisco street. The Dragon then tries to assault her in her vehicle, after which, Prue manages to escape to a nearby park. Just before her sisters are able to save her, the Dragon kills her. Not knowing what else to do, her sisters track down the Genie and force him to help them bring Prue back to life. The Genie and the sisters successfully manage to trick the Dragon, allowing Phoebe to wish Prue alive again. Brought back to life, Prue and her sisters vanquish the Dragon forthwith.
Prue's character becomes more developed in the third season, seriously taking the role of leadership for the Charmed Ones and dedicating most of her time to hunt demons and puzzle together the Triad's plans: a demonic cult that has been sending evils after them for the past two years. She is more aggressive, but confident and uses more time to studying witchcraft, inventing the Crystal Cage to trap demons.
When Cole Turner, a half-human half-demon hybrid known as "Belthazor" sent by the Triad to kill them, leads Prue to a building with a "supposed innocent" who can feel other people's emotions, she attempts to help by casting a spell to relinquish his gift. This backfired, however, as the power is transported to her instead. At first, she seemed to be dealing well with the feelings, but soon begins to pick up all the negative feelings from half the city, which begin to crumble her. Her sisters find out that the innocent is really a demon who had received the power from an empath. The original empath teaches her to deal with the power, not by fighting back but by embracing the emotions. This allows her to channel the emotions into her own powers and vanquish the demon by making him feel all the pain that she'd picked up. By vanquishing the demon, this power is removed from her forever, though it gave her powerful martial arts skills, which retained in her for the rest of the season.
When Cole becomes romantically involved with Phoebe, who was unaware of his true identity at the time, Prue finds him suspicious and tells her to be careful with him. Her dislike turns to hatred when they find out that he is really the demon, Belthazor. Before Prue and Piper can vanquish him, however, Phoebe fakes his death to protect him. A few months later, she finally tells them the truth, and Prue does not take it well at all. Cole returns soon after, and aims to become good by helping them protect innocents and fighting evil. At first, Prue is reluctant to his help, but learns to tolerate his relationship to Phoebe, and eventually to trust him.
Victor returns to San Francisco again after three years and Prue has to once again go through the same issues with her father. Prue's turning point with her father was after she and Victor were sucked into the The Ice Cream Man's Magical Truck; The Nothing was about to suck Prue into oblivion but Victor grabbed her arms, never letting go, saving her from the Nothing. After they are resolved, Prue embraces him into her life again and Victor promises to stay in touch more often, buying an apartment in San Francisco.
On one occasion, Prue started having recurring dreams of a dangerous man named T.J. that hung out in a nearby bar, without knowing that her astral form was being used by her repressed emotions to get away from her responsibilities. After a murder outside the bar was blamed on Prue, the police started to look for her. At Piper and Leo's wedding, T.J. crashed the ceremony on a motorcycle to rescue her, just before the police came. Phoebe eventually talked astral Prue into getting herself together and Darryl, Leo and Cole found the real killer.
Prue later encounters a Demonic Infector who carries a special box of each of the Seven Deadly Sins bottled by the Source, at the Source. The Infector infected Prue with the sin of Pride, the most deadliest of all the sins. Prue became extremely prideful and confident in herself; so much so she risked her life going into a car dealership in which hostages were taken by a crazed man. Prue was shot and didn't even feel it because of the adrenaline created by the sin. She was later relinquished of the sin after the destruction of the Infector.
Prue was the first to encounter the Angel of Death when demons known as Seekers targeted a young police officer hired by Reece Davidson. Prue was able to see a shadow following around the young woman and was determined to find out what or who it was. Prue discovers that it was an Angel of Death and witnessed the brutal killing of Reece by the Seekers. She then confronted the Angel who told her Death is inevitable, it is a part of life and that it is nothing that can be stopped. Prue also casts a spell to Track a Banshee and is in turn transformed into a dog. As a dog, she met a man after being hit by a car.
Prue meets her death in the final episode of the third season, when the demon Shax comes to kill a doctor. During this attack, the Charmed Ones are exposed as witches and Piper is shot by a crazed woman named Alice Hicks; to save her sister Prue uses her telekinetic ability against all the reporters and spectators that have gathered in front of Halliwell Manor who were preventing Prue from taking her sister to the hospital in time. She eventually dies from massive blood loss and Prue is completely traumatized and devastated. After time is reset by Tempus Shax attacks again at the Manor zeroing directly in on the doctor, Prue manages to shove him out of the way, but takes the hit into herself and flies into a wall. Without Phoebe to drive away the demon and Leo to heal her, she dies from a strong hit in the back of her head caused by crashing both into the wall and the floor, as well as a massive loss of blood.
With her death, the Power of Three is temporarily ended until her long lost half-sister, Paige Matthews, returns to the family and recreate it, taking her place in the Power of Three.