"DESPERATE HOUSEWIVES - ""Assassins"" - Susan's life hangs in the balance after being trampled by the rioting mob on Wisteria Lane; the fate of Paul Young is revealed following the aftermath of the riot, but who shot him?; Keith moves in with Bree but is shocked when Orson pays a surprise visit; Gaby finds it difficult to purge all traces of Grace from her life in order to repair her relationship with Juanita; and Renee wrestles with telling Lynette the truth about her past with Tom, on ""Desperate Housewives,"" SUNDAY, JANUARY 2 (9:00-10:01 p.m., ET) on the ABC Television Network. (ABC/DANNY FELD)MARCIA CROSS"