Stingray - Season 1 - Eps 35: The Master Plan
During a Terror Fish attack, Stingray is damaged. When Troy goes to make repairs, an Aquaphibian poisons him with some purple liquid. At Marineville, the doctors can't find a cure. Without treatment, troy will die within four hours. Titan has the antidote but will only send it exchange for Marina. Commander Shore refuses but Marina makes up her mind and returns to Titanica. Titan keeps his word and sends the antidote. Once recovered, Troy must come up with a plan to rescue Marina.
About Stingray

Title: Stingray
First Air Date: 1964-10-04
Last Air Date: 1965-07-04
Status: Ended
Rating: 6.8/10 (from 17 votes)
Language: EN
Seasons: 2
Total Episodes: 40
Network: Associated Television
Genres: Action & Adventure, Sci-Fi & Fantasy
Production Companies: AP Films (APF), ITC Entertainment
Synopsis
A British children's Supermarionation television series.
Cast

Lois Maxwell
Lt Atlantis Shore

Don Mason
Captain Troy Tempest

Ray Barrett
Commander Sam Shore

Robert Easton
Lieutenant George Lee Sheridan