Escaping from China with a microfilm of the formula for the mysterious "Lotus X", Lord Southmere, a Queen's Messenger, is chased by a group of Chinese spies.

Pebble Island, a breeding ground for seals is to be sold to a Conservation Group. Mike, Kate and Ben are horrified to find that until the sale is completed, permits have been granted for two professional killers to shoot seals for their skins.