Season 4, Episode 17: Free
Original Air Date—18 May 2008
In the season final, several residents of Wisteria Lane are faced with deadly threats; Adam is held captive by the deranged Wayne who physically tortures him for information as to Dylan's origins... and what happened to the real Dylan Davis. Ellie, now a fugitive, contacts Gabrielle to help her retrieve a teddy bear from their house. Tom and Lee finally have their commitment ceremony in the form of a block party on Wisteria Lane. Lynette is forced to cater to the party while Tom refuses to help out because of the Kayla case. Meanwhile, Susan realizes she will soon lose someone she loves when Julie is accepted into Princeston University early and will be leaving town soon. Also, Katherine Mayfair's secret about her past and of what happened to Dylan is finally revealed after Wayne takes her and Bree hostage in her house.

Source: IMDB