Robbie MacFarlane, is an insurance investigator for whom two families dying inexplicably suddenly on a ski-ing holiday is just another case. Find the cause - poison, infection - report back; move on. Only this one's not as simple as that. There are other sudden deaths back in Plymouth - a fisherman, a yachtsman. No obvious links to the dead families, no obvious clues. And as Robbie and his new friend, the young marina manageress, Sally Miller, edge closer to the truth lethal, as yet unseen forces conclude they must be stopped at all costs.