"The Sun is being destroyed from inside out by a type of highly stable form of matter that renders nuclear fusion impossible, by turning common matter on its own kind. The only hope is to send a team of astronauts to detonate a massive, highly energetic bomb, able to destroy this strange matter and restore Sun's natural state.
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."