Charlie is annoyed to find that Kandi has been living in his house for some time without him knowing, but is even more distraught by his own sexual dry spell.
Robin insists that Ted get rid of his collection of gifts from old girlfriends, but she balks when asked to part with her own stash; Barney puts on a play.
Barney hires a little female "entertainment" for Marshall's bachelor party, but after Lily reveals a secret about him, Marshall may want a new best man.
Ted's new girlfriend becomes jealous when she hears a story of how the guys met, and Barney decides that she has jumped a few points on his "crazy scale."
Alan forms a platonic relationship with Jake's teacher, as he enjoys the intelligent conversation they share; Charlie helps Jake rehearse for his school play.
Charlie tries to convince himself that he is over Mia when she returns to town; Mia makes a bizarre request of Charlie, and he makes an equally-unusual appeal.
When Charlie and Mia's families meet, a catastrophe is born which threatens their wedding plans; Alan and Jake wonder where they'll live after the wedding.
Charlie gleams in the return of his bachelor pad once Jake and Alan move out, but Alan and Kandi don't last long, sending him and Jake right back to Charlie's.
Alan is guilt-ridden when he realizes why Charlie didn't marry Mia; Charlie's new rock star neighbor won't stop wailing, causing Charlie to lose his cool.
After crashing while attempting to impress a new girl by surfing, Charlie shares that he's seen a vision of his late father, who made a horrific request of him.
Alan hires Judith's former lawyer when he becomes engulfed in a custody battle over his and Kandi's dog; Jake is reluctant to heed Charlie's dating advice.
Alan is elated when Judith is to remarry, as it would signal the end of his alimony payments; Jake can't stand his future step-father, causing problems for all.
Charlie pursues the mother of Jake's girlfriend, upsetting his nephew; Alan suffers from a bout of insomnia and attempts to combat it, failing miserably.
Fed-up Charlie reaches his breaking point during a double-date as penny-pinching Alan continues mooching; Jake is left at home by himself for the first time.
Charlie's new live-in girlfriend butts heads with Berta; Alan tries to sell the condo that he bought for he and Kandi, but she seduces him to change his mind.
Charlie is confident in his plans to get laid on Christmas Eve, but his friends and family play spoilers by loitering at the house, hijacking his attempt.
Berta discovers that Alan has been secretly dating her daughter, but is unexpectedly joyous about the ordeal; Alan is already contemplating an exit-strategy.
After yet another confrontation with her mom, Kourtney becomes even more frustrated with Kris; Kendall and Kylie begin internships at Seventeen Magazine.