Joyride — Jack Ketchum

Carole and her lover, Lee, knew there was only one way to get rid of Carole's abusive husband for good. They planned every detail. And they thought they had committed the perfect crime. But a stranger named Wayne saw what they did, and he was thrilled. Now Wayne wants to be their friend. He wants to take Carole and Lee on a road trip straight to hell so his new friends can enjoy an all-out killing spree that can only end one way...