The U.S.S. Avenger/NCC-74206 is returning from a tedious patrol mission just as a massive ion storm – a Century Storm – was cutting a swath across the Fourth Fleet’s operational region. After emergency shipfitting to withstand the deleterious effects of the storm, the Avenger is dispatched to a rendezvous with a Federation ambassador’s ship. The consular ship has not yet been hit by the storm, but is in the path of it, with no easily navigable way around it. It’s a race against time and nature to rescue the ambassador, her staff and the crew of her ship.