The Exxon oil rig, Scylla, is a free-floating, fifth-generation Bingo 8000-series semisubmersible oil drilling unit. Unlike platform rigs, the superstructure floats four stories above the surface (and three stories below) on eighty-two-foot-high vertical columns attached to two enormous 390-foot-long pontoons. Twelve mooring lines anchor the structure to the seafloor.

Three continuous decks sit upon the Scylla’s base. The open upper deck, as long and wide as a football field, supports a seventy-two-foot-high derrick that contains the drill string, made up of lengths of thirty-three-foot steel pipe. Two immense cranes are positioned along the northern and southern sides, with an elevated octagonal helo-deck covering the west deck. The control and engineering rooms as well as the galley and two-person cabins are located on the middle or main deck. The lower or machinery deck houses the rig’s three 3080-hp engines as well as the equipment necessary to handle a hundred thousand barrels of crude oil per day.

Although the superstructure is filled to its 110-person capacity, not a drop of oil flows through its drill string. The Scylla’s lower deck has been hastily gutted to accommodate myriads of NASA’s high-tech multispectral sensors, computers, and imaging systems. Support equipment, tether cables, and operator control boards for three ROVs (Remotely Operated Vehicles) sit next to bundles of steel pipe stockpiled along the semienclosed lower deck.

Positioned at the very center of the concrete and steel decking is a twelve-foot-diameter circular hole, designed to accommodate the drill string. A soft emerald radiance rises from the sea, filtering through the gap to bathe the ceiling and surrounding work area in an unearthly green light. Technicians overcome by curiosity pause every so often to sneak peeks at the artificially illuminated seafloor, located 2,154 feet below the floating superstructure. The Scylla is positioned directly above a massive, tunnel-like aperture located along the bottom. Somewhere within this mysterious five-thousand-foot pit lies the source of the brilliant, incandescent green light.

Naval Commander Chuck McKana and NASA Director Brian Dodds huddle over the two technicians operating the Sea Owl, a six-and-a-half-foot ROV, attached to the Scylla’s winch by a seven-thousand-foot tether cable umbilical cord. They stare at the ROVs monitor as the small submersible reaches the fractured seafloor to begin its descent into the glowing vortex.

“Electromagnetic energy’s increasing,” the ROVs virtual pilot reports. “I’m losing maneuverability—”

“Sensors are failing—”

Dodds squints at the bright light glaring from the sub’s minicam monitor. “How deep is the ROV?”

“Less than a hundred feet into the hole—God dammit, there goes the Sea Owl’s electrical system.”

The monitor goes blank.

Commander McKana runs his stubby fingers through his graying crew cut. “That’s the third ROV we’ve lost in the last twenty-four hours, Director Dodds.”

“I can count, Commander—”

“I’d say you need to focus on finding an alternative way in.”