As I am primarily a fan of romantic (though not overly soppy ones) films, I found this thriller to be quite exciting, though it is quite dated, now - more than obvious that it was made on the crossover 70s-80s.
Agree with other reviews that the underwater scenes are very nicely shot and quite impressive.
I must say that I thought most of the actors did a more than adequate job, and that it may be the script and the dramatic direction that leave a little to be desired, though the actors more than make up for this, meaning that while watching for the first time it is quite absorbing enough to distract from any now embarrassing aged moments from which we are glad to have evolved in more modern productions.
Prunella Ransome was very good as the plucky and determined heroine searching for her sister, and I thank the director for the very limited use of bathing-suit scenes, as this can easily put one off the story.
Pamela Salem gives a competent and nicely misleading performance as David Malcolm's (Seagull Island's owner)cousin, and is enviably beautiful, as usual - a treat for the husbands!
Jeremy Brett as the mysterious, respectable Englishman owner of Seagull Island is fantastic, as usual, and does not fail to impress. His acting is, as usual, very impressive and exciting. His skill, in part, keeps you guessing until the very end - a very exciting end, I must say, and (now comes the shameless gushing) he makes for a nice piece of eye-candy for the ladies, as usual!
Overall, though this is no cinematic masterpiece and probably a little disappointing for die-hard thriller fans, this is an interesting and good-looking film, modern for its time, and a lovely treat for all Prunella Ransome, Pamela Salem, Jeremy Brett and even Nicky Henson fans.
