Holly Alto is a pre-created Sim that once lived with her father and mother. For a short time as a teenager, she had a romantic relationship with Michael Bachelor, but when his family moved away (accidentally leaving Bella behind) they lost contact and she gave up on him. Her little brother, Ian, was born shortly after her second son, but due to his impatience to age up he grew into a teen a day before her first. She is deeply in love with Kalei and has the "Eternally Faithful" moodlet.
Holly was a lonely kid. Her parents didn't understand why she was such a Goody-Two Shoes; Vita hated her and Nick always picked on her. Her only friend was Bebe Hart, and even Bebe didn't always make the best effort to call or hang out, because due to her being a vampire it was hard for her to hang out during the day. But Bebe realized how lonely Holly was, and she introduced her to Michael Bachelor, a sweet guy and overall likable. She really liked him, but his mother and father decided it would be a good idea to move away from Sunset Valley to some other place, even though they didn't realize that Bella didn't get on the plane with them.
Bebe aged into a Young Adult a day before her, and when she finally did she decided to stay with her parents until she could find a new place. She heard from Bebe that she was pregnant, and she was delighted when Bebe asked her to be the godmother. She accepted happily and was ecstatic for Bebe when Chrystal was born.
Holly was walking home from the grocery store when she met Kalei. He was attractive, mysterious... pretty much everything you could want plus some. She didn't think like that at first, but Kalei was a Charismatic sim so they were instantly best friends... and when Kalei asked to be BFFs, she just couldn't say no! She was asked to move into his house by the Keaton ranch, and she happily joined him. This is when Holly also joins the Law Enforcement career.
When she moved in, she learned that Kalei was Chrystal's dad, but it never occurred to her that he could be the kind of person to date someone, get them pregnant, and leave. At the time she moved in, he was seeing Erin Kennedy, who also lives with him. He started to flirt with her, and though she didn't take him seriously she knew there might be some competition...
When it starts to get intense between Kalei and Holly, she asks Kalei if he would break up with Erin to be with her. Holly knew that it would be wrong for him to abandon Erin's baby and kick her out, but she already feels a mutual dislike for Erin and she is convinced that Kalei likes her back. He says he would, and when she finally asks him he shyly kisses her, giving Holly her first kiss, and tells her that it's over between him and Erin, though the two don't become boyfriend/girlfriend yet.
Holly hears from Kalei the next morning that Erin has given birth to a baby boy, Drake, and he also tells her that Erin wishes her luck with Kalei. Kalei asks Holly if she will WooHoo with him, but she does not want to risk getting pregnant, something that Kalei is glad to hear.
Holly is painting while Kalei is hosting a party and walks in on him having WooHoo with his new girlfriend, one that she was unaware of: Zelda Mae. She is distraught and she asks Kalei to just be friends. Though her heart is broken and she hates Zelda now for stealing Kalei, she stays in the house to make Kalei feel guilty, even when Zelda (who is also a witch) moves into the house with them. Holly notices that Kalei flirts with everyone, including Tuesday Sears, Blair Wainwright, and the new maid, Kate.
Zelda later gives birth to twins, explaining the huge belly: Angel and Jaclyn. Holly is sick when she hears noises coming from the bedroom one day because she knows that it is Kate, the maid, not Zelda who is at work. Kate is Flirty and Charismatic, so she is able to seduce Kalei as well as get Zelda out of the house, but unsuccessfully Holly, as Kalei refuses to let her go. She is touched by this kind gesture and her feelings for Kalei return.
Kalei hires another maid, Lester McCarter, who takes Kate's place. Lester originally flirts with Kalei, and since Kalei refuses he moves on to the less-attractive Kate, though surprisingly not Holly. Kate is pregnant at the time, and she easily is seduced by Lester's advances. She breaks up with Kalei (the first time that Kalei has not broken up with one of his girlfriends) and goes for Lester. They move out of the house.
Holly goes to comfort Kalei, and all of a sudden the feelings come rushing back stronger than ever before. Before they know it they are making out passionately on the bed, and Kalei apologizes for everything. In the heat of the moment, Kalei begins to initiate WooHoo, out of love and not just for fun. Holly has her first WooHoo with Kalei and happily becomes his girlfriend.
When Kalei tells her that he wants to move into the old home of Beau and Victoria Andrews, she tells him that she has to move in with her parents for a while as they are getting older. She breaks the news to her parents that she is pregnant, but the only thing they have to say to her is that they hope their grandchild isn't like her. She is heartbroken by this and decides that she will not try to stay in touch or visit her parents.
Alex is born two days later, and much to her mother's and father's happiness, he is born with the Evil and Heavy Sleeper trait. She is very upset by this; she does not want to give her parents an opportunity to worm their way into her family life, as Rylan already shows too much similarity to Vita at this point, even inheriting her brown hair, but Holly's green eyes.
Kalei invites her back in to live with him once he hears of Alex's birth, and he instantly makes an effort to care for him... and for her. He proposes and she accepts, though more unwillingly allows him to take her last name: she was looking forward to distancing herself from the Alto family once and for all.
Kalei is really making an effort and is good at it, but with all the crying and screaming and Holly working and his new profession, he hires a live-in maid, Estelle Bloom. Holly is too busy with work to really care about Estelle, though she appreciates all the work that she does for baby Alex.
At the end of Alex's toddlerhood Holly is shocked twice: both she and Vita have become pregnant! Her son, Rylan, is born a day before her brother, Ian. She also attempts to bond with Vita more, to little avail. When the two age up into toddlers and Alex into a child, both show striking similarity to Nick.
At school, Alex meets a beautiful young woman named Falcon Kerry. She is around Alex's age and is in his class. The mother and father approve of Alex's crush and say that he can date her if he chooses to when he becomes a teen. They also make an effort to become acquainted with Falcon's mother and father, as well as her brother and sister.
When Kalei learns that Bebe's old house has been condemned after she moved into the house next to Gobias Koffi with Leighton and her parents, he is upset. He knows the house means everything to Bebe, especially after her mother Dorie died in a fire a while back. He also knows that her new fiancé, Leighton, is left alone in Sunset Valley, choosing to stay in Sunset Valley with her while his mother and son have moved away. Kalei and Holly discuss the situation with Bebe and she tells the couple that she wants nothing to do with the house. She sells the lot to them and the house is demolished, but Kalei works to build a new house there, a beautiful one, that he and his family can live in for future generations.
The finished product is a house that he decides to call "Cherry Pink". The family of four move in along with Estelle. When Rylan ages up into a child, he and Ian both get the same trait when aging up, Over-Emotional.
Ian is tired of being even younger than Rylan, and on top of that he knows that his parents are going to age up into elders in a few days. So he has his parents buy three birthday cakes, and he blows his out before they can do anything about it. He gains the Artistic trait when aging up.
Alex ages up a day after Ian does, Becoming a teen with yet another good trait, Genius. His crush, Falcon, ages up on the same day, getting the Frugal trait. Kalei is delighted to see Alex and Falcon become closer, and is overjoyed when Alex comes home late one night and tells his parents that he has asked Falcon to become BFFs... and she accepted!