The birdwatching weekend in Cornwell becomes memorable when a small band of fanatical birdwatchers aboard the 'Jessie Ellen' - among them detective George Palmer-Jones - sights a seabird that has never been recorded. In the excitement, no-one notices the sudden absence of Greg Franks, the most aggressive birder of them all. Later, Frank's corpse, the head bludgeoned, is found floating in the sea and George unhappily shoulders the burden of finding his killer. Who hated Franks enough to kill him?