Blake's 7: The Liberator Chronicles: The Armageddon Storm Part 1

Del Grant, mercenary. Kerr Avon, freedom fighter. Former friends. Former enemies. Linked forever thanks to Grant's sister, the woman Avon loved. The woman Avon killed. Now their paths cross again. Grant has learnt of the existence of the Armageddon Storm, a terrifying new Federation superweapon. Avon finds himself in a race against time, with his crew's lives hanging in the balance. But what will Grant do when he finds out about the blood on Avon's hands?