Showing The Farther Shore by Christie Golden

When an unstoppable Borg plague breaks out upon Earth, blame quickly falls on the newly returned crew of the Starship Voyage ™. Did Kathryn Janeway and the others unknowingly carry this insidious infection back with them? Many in Starfleet think so, and Seven of Nine, in particular, falls under a cloud of suspicion. Now, with a little help from the Starship Enterprise ™, Admiral Janeway must reunite her crew in a desperate, last-ditch attempt to discover the true source of the contagion and save Earth itself from total assimilation into a voracious new Borg Collective. But time is running out. Has Voyager come home only to witness humanity's end?