After Alan has been slowly sneaking Melissa into Charlie's house, Charlie is finally upset enough to confront Alan about it.  However, Chelsea convinces Charlie to let Melissa move in to make Alan happy.  Charlie reluctantly does but when Alan and Melissa throw a party, it's the last straw and he takes off to a hotel room, leaving the other three to run the household.  Alan, meanwhile, ends up pissing off the girls when he declares himself head of household with Charlie gone.  He gets kicked out and heads over to crash with Charlie and a bottle of scotch.

While the girls are busy running the household, Charlie and Alan hatch a plan overnight to back the power.  They send their mother Evelyn over to talk to the girls.  She tells Chelsea and Meslissa she's so proud of them for being friends and living under the same roof given the fact Melissa has slept with Charlie.  Chelsea gets extremely pissed and Melissa moves out.  Battle won.

With the other girls gone, Jake has the neighbor's daughter, Celeste, come over for dinner that night and makes the guys make a vegetarian meal for her.  They realize they're still whipped... but by the third generation.