Dead Girls Never Shut Up — Susan Stec

Toni's grandmother is a psychopath. Her sister is a ghost. Her boyfriend is possessed. And she has no idea who she is. Summer vacation is ruined when Toni's twin sister, Sara, inadvertently, but unmistakably, slices her own throat with a steak knife in the middle of their staged double date. Unbeknownst to Toni, instead of walking into the light, Sara stomps off in the opposite direction; totally pissed she didn't die in her skinny jeans. That's when Sara finds out their grandmother has a gift for talking to dead people. Dear old Granny's determined not to be the last necromancer in the family, but with the death of her promiscuous granddaughter, her only option is Toni, who must remain a virgin until her eighteenth birthday and then have sex with a guy Granny has chosen for her. Sara's not having any of it because Granny's guy is the same one that assisted in her untimely death. Unfortunately, Granny knows Dead Girls Never Shut Up.