The Stalker

Very early one Saturday morning, Mike's phone rings."Nice day for a little kayak trip, eh?" says the deep, echoing voice. "But I wouldn't go out if I were you."
Mike's business is guiding visitors on kayak tours around the islands off the west coast. This weekend, he'll be taking Liz, his new cook, and two strangers on a kayak tour. Soon, his phone rings again. "I'm watching you," the caller says. "Stay home."
Mike and the others set off on their trip, but the stalker secretly follows them. Who is he? What will he do? The Stalker will keep you guessing until the end.