Jack welcomes Mackenzie as she arrives at the Chancellor Mansion. Billy is shocked to see her. Mac says she came back because she heard that her grandmother might still be alive. Billy introduces Chloe and Mac to one another. They hear the commotion in the other room, and Jack wonders what all the noise is. They all go to see what is going on and find Katherine and Jill fighting in the cake. Chloe is displeased that her wedding cake is ruined. Nikki tells them all they have good news. Katherine says she now has proof that she is Katherine Chancellor and that, "this thing," is not her daughter. She gestures toward Jill. Mac and Billy are both taken aback.
Sharon apologizes for being such a mess and crying on Nick's shoulder. She says she had a terrible day - she left Chloe's wedding because she wasn't feeling well, and then had to deal with Phyllis. Nick said he saw Phyllis being escorted out of the building. She regrets that she and Nick are fighting over her again and asks him to leave. Nick tells her he isn't going anywhere and that Phyllis needs to stop obsessing over her. Sharon reminds him that he recently told her to stop her crap, and Nick admits that he did, but he did so because he was angry that Noah was so upset. He tells her that he is worried about her and wants to understand what is going on - she isn't acting like herself. Sharon asks him to leave it alone, that he should be the last person trying to help her after what happened up at the cabin. Nick tells Sharon that he cannot watch her unravel. She asks him to take care of Noah and to keep Phyllis away from her while she tries to put her life back together. Nick says he will take care of Noah and do his best to keep Phyllis away from her.
Nick leaves, and finds Phyllis outside her door. Phyllis says she didn't want to believe it, but here Nick is coming out of Sharon's room - again. Nick prevents Phyllis from going into Sharon's room and tearing her apart. He guides her away from the room, while Phyllis insists that her not touch her.
Brock welcomes Mac back. Jack says that this news calls for a celebration - Katherine is back! Billy admits he heard Katherine tell the doctor she was a fraud in the hospital, and she explains she had to do that because the doctor didn't believe her and she needed to lie to get out of the hospital. Katherine says the attention of everyone should go back to the bride and the groom, and says she's going to put on cleaner clothes. Nikki takes Murphy for a tour of the Chancellor mansion. Jack wonders if Ashley noticed the way Billy looked when Mac showed up and when they found out they aren't related. Ashley said she noticed and she thinks that all of this is a bad omen - this marriage is a mistake. Jack reminds her that this is the only way Billy can keep Cordelia. Chloe and Colleen talk. Colleen tells her she had a moment of weakness when she stood up for Chloe as her matron of honor. She tells Chloe she should get to know Mac - she has a lot of interesting stories to tell. Billy tells Mac her timing sucks. Mac says Cordelia is beautiful and that she's happy for Billy. Chloe comes over with the baby, and Mac says she needs to go clean up. Chloe says she's sorry about Billy's mom. Billy tells Chloe he can't believe she isn't Katherine's daughter!
Cane arrives at the Chancellor mansion and apologizes to Katherine for not believing her. He says he said some awful things to her, and she tells him it's already forgotten. Katherine introduces Cane to Murphy and they each seem glad to meet one another. Cane finds out that he and Billy are not related. Katherine tells both Billy and Cane that they are both still her grandsons in every way that counts, and that nothing is going to change between them. Jill goes over to Mac who is cleaning up the cake mess and tells her that she never approved of her relationship with Billy, but she must be wondering what might have been. Mackenzie tells Jill that she and Billy were a long time ago and that she's gotten over him.
Esther tells Chloe about Mac and Billy's history. This worries Chloe. She fears that if Billy loved Mac once, he'll fall for her again, but Esther tries to reassure her. She tells Chloe that Billy wouldn't be with her if he didn't want to be - whether she had a baby or not.
Billy goes outside to get some air and to think. Jack follows him, and Billy admits he's been thinking about Mac a lot lately and how different his life could have been with her. Jack tells Billy that he and Mackenzie were a long time ago - he doesn't even really know her anymore. Jack also reminds him that he'll risk losing the baby if he leaves Chloe.
Chloe comes downstairs and Cane makes fun of her for not bagging a Chancellor after all. Chloe says she doesn't care if Billy is a Chancellor or an Abbott because he cares about her. Cane scoffs at her. Billy comes over to Chloe and asks her if she's ready to leave, and she responds she thought he'd never ask! They say their good-byes, and leave. On the way out, Cane wishes them a happy honeymoon. Katherine thanks Jack and Ashley for believing her. She says she can't wait to see what the future holds, and Jack says he can't either. Cane and Mac realize they have something in common - neither of them knew they were a part of the family. Katherine approaches Jill and says she noticed she kept everything in Katherine's room the same. Jill admits she'd give anything to have her mother back, but Katherine is not her mother. Jill says she spent six years of effort and time on this ridiculous relationship. Jill says she owns half of the Chancellor mansion and always will, but she won't live under the same roof with Katherine. She says she's moving out. Katherine and Brock try to convince her to stay to no avail. Jill says her good-byes and leaves.
Jack and Ashley go to the Club to celebrate. Jack thinks there are good things in store for Jabot. He wonders if Sharon will show up, and Ashley reminds Jack there are a lot of problems in his marriage. Jack takes responsibility for the problems in the marriage. Ashley tells Jack it may be time to cut his losses and move on with his life, but Jack says he can't do that right now.
When Phyllis returns home, she and Nick begin to argue. Nick says he's sick of Phyllis being obsessed about Sharon. Phyllis admits she's sick of it, too - she hates being paranoid and jealous and feeling this pain in her stomach, but he did this to her! Phyllis tells Nick that his sweet Sharon is a thief, a liar, a manipulator, and a tramp! She says she has proof that she's been with different men, and wants to know if Nick asked her about being with Billy. Nick says he didn't. Nick wants to know why Phyllis cares who Sharon sleeps with as long as she isn't sleeping with him. Phyllis reminds him that Sharon has slept with him and will again in the future. She reminds him that he said he loved her. He reminds Phyllis that he said he loves Phyllis, too. Phyllis insists that Nick needs to see who Sharon is, but Nick tells her he knows who Sharon is - it is Phyllis that he is seeing for the first time. He tells her he isn't sleeping there tonight.
Once they are alone, Chloe asks Billy about Mac. He says he hasn't seen her in years. He asks Chloe if this is really what she wants to talk about on their wedding night. He kisses her.
Jill and Cane talk at the Club. Jill admits to Cane that her relationship with Katherine felt right, and now she knows why - they aren't related. Cane tells her that just because they are related doesn't mean they have to be enemies. Jill tells him that she thinks they were born to be enemies.
Nikki reminds Katherine to call Mitchell Sherman at the Chancellor mansion so that he can work on getting her death certificate revoked and reversing her will. Katherine says some people won't be happy about losing their inheritance, but Nikki tells her that if they care more about their inheritance than Katherine, then they didn't deserve it in the first place! Nikki embraces Katherine.
Brock tells Mac she doesn't look so well. She finally admits she wonders what would have become of her and Billy.
Jack goes to Sharon's room to tell her the news about Katherine's DNA test and the fact that Katherine and Jill are not related. Jack says it is nice when people have an opportunity to start over. He wonders if Sharon will give him just one more chance - even though he's had plenty of second chances. She tells him she'd only hurt him. She reaches into a drawer and hands him divorce papers. She said she finally signed them and wants him to do the same.
Jack signs the divorce papers down at the bar. He sees Jill and asks her if she was kicked out of the house already. He says next she'll be losing Jabot and Chancellor Industries. Jill tells Jack to shove it - she's not in the mood. She leaves.
Murphy and Katherine get settled in her bedroom.
Chloe awakens to find Billy gone.
Mac sits outside, and is startled when she sees Billy.