A group of yachting tourists find themselves stranded on an island, all alone except for a strange old Nazi SS commander (Cushing)...and a posse of undead zombies who dwell underwater and rise at their old leader's bidding!

Eerie low budget fun, with a setup reminiscent in tone to Let's Scare Jessica To Death (1971).

Our heroine (the always pleasurable Adams) bookends the film by narrating the events of her nightmarish ordeal.

Acting ranges from very good (Adams and Cushing) to mediocre. But the real triumph of Shock Waves is its surprisingly effective mood of seepy, mossy danger.

Of course, this is worlds better than the similarly-themed, but awful, Jean Rollin-Jess Franco collaboration Zombie Lake (1980).