'Young Zaphod Pulls It Off' by Douglas Adams

Zaphod, currently running The Beeblebrox Salvage and Really Wild Stuff Corporation, is hired by two officials from the Safety and Civil Reassurance Administration to take them into the ocean depths of a small green-blue planet on a mission to locate the crashed remains of the Starship Billion Year Bunker, which allegedly could one-hundred-percent positively never crash. Six months ago, this secure vessel was carrying by-products from a secret process that were to have been disposed of in a black-hole, but when the pilot decided to do a detour to pick up some lobster, the ship crashed into the sea. Zaphod and his associates locate the ship, only to discover that the crew are dead, and that one of the three members of ‘cargo’ has escaped…

Notes:
*Featuring Zaphod Beeblebrox

*Included in 'The Utterly Utterly Merry Comic Relief Christmas Book' published by Fontana Paperbacks in 1986