The season starts after Charlie was killed in an accident in Paris. He had supposedly proposed to Rose and they had run away together. A heartbroken billionaire, Walden Schmidt comes into the picture and forms a relationship with Alan. He then offers to buy Charlie’s house, which had been left to Alan. Walden buys Charlie’s house and soon moves in. Alan on the other hand has to move in with his mother, Evelyn, but Walden later asks him to move back in with him. Walden tries to get back with his wife, Bridget, and she eventually agrees to give him a chance to prove himself. Alan and Jake have to share a room back at Walden’s house. Meanwhile, Walden and Jake to know each other, and Jake decides to take Walden’s route by quitting school. Walden and Judith end up making out when he tells her about his troubles with Bridget.

Walden meets Courtney in his endeavor to get over Bridgett and they hit it off. Alan knowing that Courtney is only interested in money confronts her about taking advantage of Walden. He also calls in Bridget for reinforcement and Walden is forced to make a choice between Bridget and Courtney. When he chooses Courtney, Bridget is forced to blackmail her into leaving Walden alone. Alan discovers that Lindsay once starred in a porn movie and confronts her about it. When Alan and Lindsay have a discussion about honesty, he decides to tell her all his secrets. After revealing all his secrets, she throws him out and the two split. Lindsey later comes over to apologize to Alan but is told that Alan is not home. Walden throws Alan off the deck in order to truly tell Lindsay that he is not home.