Alan and Lyndsey finally have the opportunity to introduce their mothers to one another; Jake and Eldridge ask Walden to drive them to a high school party.
Walden must break the news to Zoey that he plans on going into business with his ex-wife; Alan and Lyndsey come to terms with their moms' new relationship.
Chrissy and Janet turn against each other after reading an advice column in which a reader has written that he is dating one of his two female roommates.
Larry attempts to woo Janet after she comforts him following an unsuccessful date, and Janet attempts to change Larry's mind transforming into someone else.
Chrissy and Jack jokingly handcuff themselves together, but problems arise once the two realize that they do not have the key and Jack refuses to miss a date.
Janet hires an art student to redecorate her room, but Chrissy and Jack begin to believe that that the artist is seeking to be Janet's surrogate father.
The roommates agree to take in an orphaned boy who has run away from home, but problems arise when the youngster begins to play both the girls against Jack.
Chrissy shares her winnings with Jack and Janet after a successful day at the horse track, but the roommates soon clash over how best to spend the money.
Mr. Miyagi is called back to Japan to be with his dying father, and when he and Danny arrive they find that an old feud and new foes are waiting for them.
A teenager moves from New Jersey to California, where he immediately becomes the target of bullies, until an elderly man teaches him the art of karate.
Amy and Robert learn living with Frank and Marie isn't going to be as easy as they had first expected it to be, when a solicitous Marie offers romantic gifts.
Charlie questions his relationship with Chelsea when he hears that Mia is back; Judith goes into labor and Charlie, Alan, and Herb rush her to the hospital.
Alan is forced into taking care of Judith's baby when his ex-mother-in-law becomes tipsy; Jake blackmails Charlie after he accidentally runs over Chelsea's cat.
Alan takes a job working for Evelyn so that he can eventually move out of Charlie's place; Charlie attempts to close the rift between Chelsea and Jake.
Alan suggests that Chelsea should get breast reduction surgery, and Charlie responds by kicking him out of the house; Evelyn allows Alan to move in with her.
After Charlie and Chelsea set their wedding date, he and Alan go out, only to awaken perplexed as the two of them are in the same bed with a strange woman.
Chelsea invites her gorgeous college roommate to stay at Charlie's after she undergoes a rough breakup, resulting in Charlie secretly hoping for a threesome.
Walden's commitment is put to the test when Zoey and her daughter come to live with him; Alan gets more than he bargained for when he moves in with Lyndsey.