Writer: Don Freeman
Artist: Stephen Dowling and Dick Hailstone
Published: 26th January 1948 - 10th April 1948 (G22 - G86)
Number of Episodes: 65
Lumiere plans to salvage the gold by descending from the “Research” in a bathysphere, from which Garth can swim to the wreck and attach cables to the gold chests. Special apparatus will then draw both gold and Garth back to the bathysphere against the current.
Whilst these preparations are made outside the cave entrance, Von Grimm’s men have neared the cave by descending from the surface down a network of lava tunnels, to await Von Grimm’s arrival. He has fooled Garth by descending hidden steps inside the crater.
However, the powerful current drags not only Garth but the bathyscape containing Lumiere and Karen, into the flooded cave. It strikes and jolts the wreck like a cannon ball, uncorking another shaft up which they are ejected in a waterspout into a cave above. The jolted wreck settles back, resealing the shaft. Basalt pillars in the caves impregnated with glowing glaucosite provide the underground with illumination.
Garth frees the dazed Lumiere and Karen from the battered bathysphere, and then explores the network of tunnels alone, seeking a way out. With his knife he carves a trail on the walls, to find the way back.
Von Grimm, with his captive Dawn, has rejoined his men. He leaves her with them whilst seeking his old escape route from the cave of the gold ship. As he and Garth converge in the tunnels, Garth is suddenly attacked by a gigantic spider emerging from a hole in the rock walls. Observing Garth’s death struggle, Vin Grimm decides to follow his marked trail, which leads him to Lumiere and Karen. He overhears Lumiere telling Karen of his plan to raise the gold ship to the surface of the Isle by dropping depth charges, forcing it up the shaft on a waterspout. He ties them up at gunpoint, then goes to rejoin his men and implement Lumiere’s explosives plan.
Meanwhile, with his knife and super strength, Garth fights free of the spiders, and then rescues Dawn from Von Grimm’s gang. Von Grimm returns, and as Garth closes with him, a recovered gangster smashes a rifle butt on his head, stunning him. During the struggles another giant spider has dragged Dawn back to its lair. Leaving Garth for dead, Von Grimm and his men return to the cave and set their explosives before withdrawing to the safety of their camp above. Lumiere and Karen are left behind to die in the explosion.
As Garth recovers he hears Dawn’s cries, and finds her embedded in a vast web: the spider—its normal prey bats—has stored her in its larder. Garth kills the spider and slashes Dawn free. They return to the cave just in time to free Lumiere and Karen, dodging beneath a rock archway as the depth charges explode. The explosion is heard up above by Grimm, and also by Captain Steel and his men, who have landed on the island to search for Garth.
Grimm leads his men to the surface to find the wreck. Below, Garth snatches a lifeboat swept from the wreck, and his party are able to sail it on the swiftly rising waters up the lava tunnels to the surface.
Up above, Von Grimm slips into a ravine now filling with the rising sea. His frightened men abandon him. Von Grimm struggles to a ledge—only to be devoured by a giant spider! Garth and his party discover the wreck now floating on the surface, whilst Captain Steel’s men capture the gangsters as they emerge, before picking up Garth’s party and returning triumphantly to Crater Island.
Synopsis by Philip Harbottle