Photo: Jill RitterBroken, bloody and a murderer -- what's not to love?Kyle Jarrow's Love Kills is a different sort of musical. Set in a 1958 Nebraska jail, the plot matches two sets of lovers -- middle-age Gertrude and Merle, teen-age Charlie and Caril -- and their attempt to understand what the other couple has done with their lives. Charlie and Caril have been apprehended at the end of their state-wide killing spree, and Merle, the town sheriff, uses his wife as a pawn to wring a confession