As two survivors of a spaceship crash, you must solve insidious puzzles to rendezvous with each other and uncover the mystery of the abandoned planet Argilus.

On 4 December 1872, the 103-foot brigantine Mary Celeste was discovered drifting abandoned in the Atlantic 590 miles west of Gibraltar. The captain's log and the crew's personal effects were found on board. The cargo was intact. There was an unfinished letter on the mate's desk, the imprint of a child's head on a pillow on one of the bunks. To this day, no one knows what became of the captain, his family and the crew of seven.

When the first humans landed on Argilus on 24 June 2083, they found towns, cities, evidence of fascinating alien technology, but all abandoned, with clear signs that the inhabitants had only just departed. Doors were unlocked, meals unfinished. Amazing machinery was still working away. But no people. It was like discovering the Mary Celeste on a planetary scale.

Earth Central wanted answers. The planet was classified Restricted and put under immediate quarantine. Experts were sent in. Three science teams - nearly a hundred of Earth's finest first contact specialists - set up science and monitoring outposts at three promising locations: Base One at Bosh's Tunnels, under Dr Angela Davies, Base Two at Symphony Harbor, under Dr Gustav Tomlin, and Base Three at Rainbow Landing, under Dr Frances Bremmer.

Because of a particularly active planetary magnetosphere, the surface teams found it impossible to contact Earth directly. Though able to make limited radio contact with one another, the constant electromagnetic interference in the atmosphere prevented messages being routed through the orbital beacon in the usual manner. At first, eager mission leaders could use shuttles to return to the orbiting expedition base ship, Tarquin, and broadcast from there, but twenty days after the expedition's arrival, Tarquin fell silent and vanished from surface radar scans. It had either left the area or - an alarming prospect - had been destroyed in orbit. The teams on Argilus were effectively cut off from Earth.

That was just the beginning. Scientists began to go missing. One by one, wherever they were working, alone or in company, personnel at all three bases started disappearing. Was it something they touched, some device they activated, some secret they discovered? No one could say. Every day, the survivors were faced with the nightmare of discovering who had vanished this time, and were left frantically, desperately, uselessly seeking answers.