Alan secretly uses Walden's money to invest in Kate's fashion line. "Welcome to Alancrest" is the 12th episode of the show's tenth season.
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Two and a Half Men Season 10 Episode 12 Quotes

Walden: You will be surprised what happens to a guy when money is tight.
Alan: Please, I have been so desperate, I have climbed into fountains at night and stolen the wishes of little children.
Walden: So you get it.

You are supposed to act like a rich guy, not a gay Bruce Wayne.

Walden