A woman whose vision of a perfect life with her adoring fiancé, Nick, and his wonderful family is radically altered when her 16-year-old, out-of-control half-sister, Shannon, unexpectedly comes to live with them.

After learning that Clem doesn’t plan to invite her father to the wedding, Nick’s parents encourage her to ask him over to their home for dinner to help repair their relationship. Also, Nick tries to teach Shannon to be more responsible at home.

Desperate for some private time since Shannon came to live with them, Clem and Nick plan a much-needed afternoon rendezvous that’s interrupted when Shannon is sent home from school for breaking the dress code.

After Clem and Nick tell Shannon she can’t go to a music festival on a school night, Shannon’s long-absent mother, Jolene, comes back into her life and tries to undermine them. Also, Freddy attempts to help matters in an effort to get back in Clem’s good graces before the wedding.

Irritated that Clem has been invading her privacy, Shannon plays a prank on her that ends up having far-reaching ramifications.

During their engagement party, Clem and Nick are both shocked to learn that the other has been keeping an embarrassing secret about how they met.

When Shannon’s bad-news ex-boyfriend, MC DJ JoJo, comes back into her life, Clem and Nick try using reverse psychology to get them to break up.

When Clem and Nick run into Nick’s ex-girlfriend at their hotel during a romantic weekend, Clem is upset to learn that Nick and his ex once lived together in the same apartment they live in now. Also, Shannon’s friend tries to persuade her to throw a big party while Clem and Nick are away.

After Freddy begins seeing Rose for therapy after an incident at work, he inadvertently finds himself trying to connect with Clem more. Also, Walt and Shannon try to help Nick get over his fear of his first wedding dance with Clem.

Clem feels her former “fun” life slipping away after attending Shannon’s school’s Open House and joining the PTA, and decides to liven up the low-key bachelorette party she originally asked for.

When Clem’s mother-in-law, Rose, asks her to wear her old wedding dress, Clem is touched, but afraid to tell her it’s not her style. Also, Nick tries to prove his athleticism by taking Ben’s advanced spin class.

Clem’s father surprises her with video left by her deceased mother for her wedding day. Also, Clem and Nick run into trouble getting their marriage license the day before their wedding.