Things are about to go from bad to worse on Salem.

WGN America's spooky witch drama airs an all-new episode this Sunday and ETonline has your exclusive first look at the action-packed hour featuring a crackling scene between Mary Sibley (Janet Montgomery) and Countess Von Marburg (Lucy Lawless).

Mary realizes that she may have a new ally in English doctor Samuel Wainwright (Stuart Townsend), but there's just one problem: her young son, Little John (Oliver Bell) has gone missing. 

In the sneak peek, Von Marburg assures a distraught Mary that "our little lamb is safe and sound," but obviously that's not good enough. "Tell me what you've done with him or I will rip the truth out from your heart," Mary demands.

Turns out, there's a far greater reason for why Von Marburg has kidnapped Mary's son -- and it has to do with the "greatest of all sacrifices."

Watch the rest of the scene to find out how Mary takes the terrifying news.