Stingray (1964)

S1E37 Hostages of the Deep

An extraterrestrial being residing in the ocean seizes an ex-WASP admiral and his spouse, holding them against their will. As they navigate their perilous situation, they must rely on their wits and resilience to survive the alien's intentions. With the stakes high and time running out, the couple faces challenges that test their relationship and bravery in the depths of the sea.