All-Night Party (Fear Street, No. 43) by R.L. Stine

Fear Street -- Where Your Worst Nightmares Live ... It's Cindy's birthday, and her friends are throwing her a surprise party on Fire Island. It's a private party -- no parents, no cops ... in fact, no one around for miles. Except there's a madman loose on the island. A murderer who quietly crashes the party. And he wants to dance with the birthday girl ... Annotation. Fear Street -- Where Your Worst Nightmares Live ... It's Cindy's birthday, and her friends are throwing her a surprise party on Fire Island. It's a private party -- no parents, no cops ... in fact, no one around for miles. Except there's a madman loose on the island. A murderer who quietly crashes the party. And he wants to dance with the birthday girl.