X Marks the Spot

X Marks The Spot is the 18th episode of the First Season. It aired January 30, 1965.

Synopsis
At the Pentagon, the military gives the go-ahead on Operation: Powder Keg which involves launching an experimental nuclear warhead in the vicinity of the small uninhabited islands in the Pacific, one of which is the island on which the Castaways are. Meanwhile, Gilligan and Skipper are planning on building a playroom on the island since they might be there for a long time. The Skipper soon goes on a search for the radio and finds it at the Girl's Hut, reaching in through the radio and turning it off to tease them by imitating their exercise program. When Ginger and Mary Ann discover the deception, they are not amused. They try turning the radio back on, but it's not working. The Professor discovers that the batteries have gone bad, robbing them of their only access to the outside world. This irks Mr. Howell until Lovey shows him the batteries came from his company. Fortunately, the Skipper has fresh batteries he has never used, but have gone bad in the interim. However, they are rechargeable, and he shows the castaways a high school science trick to recharge them. The process works just in time to hear on the radio that the military is launching a missile which the Skipper realizes is right into their area. Meanwhile, the military has unarmed the missile to test by itself, but they don't release the news. Still believing the impact will wipe them out, the Castaways are still making amends. Mary Ann makes pies for the Skipper and Gilligan, and as the Professor reviews his academic career to Ginger, he realizes they could be rescued as the military would send out a scout plane to search for natives and charter crafts in the flight range. As it comes, he tries signaling for it with a mirror made for the Howells, but Gilligan smashes through it on a vine as the plane passes overhead. Everyone listens helplessly as the radio announces the missile launch unaware it's been unarmed. It's announced as a perfect shot, and minutes later, it comes down in the lagoon with its after-thrusters propelling it onto the beach and into camp. The Professor thinks he can deactivate it, but Gilligan is the only one thin enough to crawl inside of it. Analyzing its schematics from a hatch, the Professor relays Gilligan the instructions on how to deactivate the non-existent explosives. All goes well until Gilligan's screwdriver completes a circuit, reactivating the after-thrusters and sending Gilligan in the missile on a trip through the jungle and then out to sea. Believing he's been lost, everyone is grieving his sacrifice. The Howells want to rename one of their homes after Gilligan, and Ginger wants to make a movie about him. Swimming back to shore, Gilligan thinks it all sounds so good that he turns around to drown himself before everyone rushes back to stop him and drag him back home. The next day, Gilligan reveals that he found the will Mr. Howell made when he thought he was going to be blown up, but when he tosses it back, Mr. Howell dives into the lagoon to get it back.

Credits
Main Cast
 * Bob Denver as Gilligan
 * Alan Hale Jr. as The Skipper
 * Jim Backus as Mr. Howell
 * Natalie Schafer as Mrs. Howell
 * Tina Louise as Ginger
 * Dawn Wells as Mary Ann
 * Russell Johnson as The Professor

Guest Cast
 * Harry Lauter as Major Adams
 * Russell Thorson as General Bryan
 * Charles Maxwell as the Radio Announcer (voice only)

Quotes

 * Radio Announcer - "And the countdown has begun on Operation: Powderkeg... Five... Four... Three... Two... One! It's a perfect shot!" Mr. Howell - "It would be."

Trivia

 * The approximate location of the Island in this episode is latitude 140 by longitude 10 degrees, which is impossible because latitudes only range ±90. However, reversing the numbers gives a more accurate location for the island.
 * The batteries in the radio die out; they have to get recharged again in The Postman Cometh.
 * In this episode, when the Castaways try to signal a search plane with a mirror, Gilligan breaks it when he swings off a roof via a vine. In The Pigeon, when the Castaways try to use a mirror to intimidate a giant spider, Gilligan again breaks the mirror!