Shawn gets a letter in the mail from his mother Virna, whom he hasn't heard from in three years. He is hesitant to open the letter, but everyone thinks he should, except Cory. Cory tells Shawn that things are going great for him now, and that nothing in the letter could be good. Despite his Cory's warning, Shawn opens the letter anyway only to find out that Virna is not his real mother. Everyone is worried what Shawn will do next, because of his history of behavior when things like this occur. Shawn assures them that he'll be okay. Jack attempts to help Shawn track down his birth mother, whose name they find out is Elaine. Their best attempts turn up no results however, and Shawn is obviously upset but understands that it was a long shot anyway.
Meanwhile, Eric is put in charge of planning a surprise birthday party for Alan, who is turning 46. Eric's off-the-wall ideas include using Morgan as a decoy and having her get sick, so he can throw the party when Alan least expects it. However, Eric soon finds out that he is the decoy, and the surprise party even surprises him. At the party, Shawn shows up and it is apparent that he has been drinking. His friends try to comfort him but he expresses his resentment over not having a mother or a father. Alan and Amy offer to adopt Shawn, because he has always been sort of an unofficial member of the family. Shawn is taken aback by the suggestion, but needs to do a little soul-searching before he gives them an answer.
Shawn goes to the cemetery to visit his father's gravesite. There he contemplates his situation and tries to sort out his feelings. Cory shows up and convinces Shawn to come back to his house. Shawn tells Alan and Amy that he really appreciates their offer to adopt him, but he will have to decline. Alan and Amy understand but remind him that the offer will always be on the table.