Walden tries to loosen Zooey up by sharing some of Berta's special brownies.
Walden has a breakdown after his relationship with Zoey ends.
Zoey and her daughter move in with Walden; Alan gets more than he bargained for with Lyndsey.
Walden tells Zoey that he will be going into business with his ex-wife (Judy Greer); Lyndsey and Alan grapple with their mothers' new relationship.
When Alan has a heart attack, Charlie's ghost (Kathy Bates) visits him.