sentences:  That summer, while the 2004 Summer Olympics were screening on rival channel NBC, the show launched another major storyline that involved a masked serial killer terrorizing the Quartermaine mansion for five episodes.The storyline was seen as an attempt to lure NBC soap opera viewers, especially due to the similarities to the recent serial killer storyline that had taken place on rival NBC soap "Days of Our Lives".In "General Hospital"'s version, the killer is revealed to be Mary Bishop, attempting to kill Emily Quartermaine but killing Sage Alcazar instead.