The Opposite of Murder

Jemma Stelling has confessed to a murder — one she can’t possibly have committed.

She has an unshakeable alibi: when Marianne Cass was stabbed to death outside her home, Jemma was at the police station confessing to a murderous obsession with Marianne and a plan to kill her in precisely the way she was killed.

So is Jemma innocent? Or is she an ingenious, cold-blooded murderer?

Can someone be guilty of the opposite of murder?