Thunderbirds (1965)

S1E49 A Bad Altitude

Title: A Dangerous Descent Plot: Dr. Claw has devised a scheme to submerge a large portion of an island, aiming to transform his mountaintop resort into the sole hotel on "M.A.D. Island." With this plan, he hopes to eliminate competition and establish his dominance over the area. As he sets his plot into motion, the stakes rise, and the fate of the island hangs in the balance.