Space-ship Icarus I failed to kick-start Earth's dying sun back into action and disappeared. Icarus II carries the last available nuclear super-bomb on a mission to try again. The navigator's oversight causes serious damage to the ship, yet returning is no longer a hope, the mission dubious.

50 years into the future, the Sun begins to die, and Earth is dying as a result. A team of astronauts are sent to revive the Sun - but the mission fails. Seven years later, a new team are sent to finish the mission as they are Earth's last hope.

Space-ship Icarus I failed to kick-start Earth's dying sun back into action and disappeared. Icarus II carries the last available nuclear super-bomb on a mission to try again. The navigator's oversight causes serious damage to the ship, yet returning is no longer a hope, the mission dubious. Having picked up Icarus II's emergency signal from Mercury, they decide to try pick up its bomb. That side-trip comes at a high cost. But an even worse surprise is lurking aboard.