Charlie has trouble keeping up with Mia's healthy lifestyle, so he begins to sneak beers, cigars, and burgers behind her back. When Mia finds out what he was doing, Charlie has to decide if he is truly in love with her or just whipped.

Alan has trouble deciding if he should bring his younger girlfriend to Jake's birthday party to meet his mom and his ex-wife. Rose tries to get her boyfriend to act more like Charlie.

Charlie is nominated for an advertising award, but he decides to boycott it because his arch nemesis always wins. The rest of his family tries to trick him into going. Rose is having relationship problems with Gordon and seeks help from Charlie.

Charlie gets tired of Alan's mooching and reaches the breaking point during the brothers' double date. Jake is left home alone for the first time.

After Chelsea discovers a nude picture of another woman on Charlie's cell phone, he blows off steam by going out for a night of drinking with Alan, Herb and his neighbor.

Charlie mourns the loss of his bachelor pad as he reluctantly allows Chelsea to move in. Meanwhile, Alan discovers there is no longer much space left in the house for him.

Lyndsey and Eldridge move into Charlie's house after their home burns down.

While Charlie and Rose carry on their "affair," Alan's chiropractic business turns into a Ponzi scheme.