After one of Tully’s birthdays ends in disaster, Kate becomes devoted to making her friend’s big day special, even if her efforts don’t always succeed.

Over holidays past and present, relationships shift — and truths are spoken — as Tully and Kate reshape their expectations for what the future holds.

Tully and Kate weather health issues and romantic entanglements, from a college dalliance to a steamy encounter that leaves an ex hot under the collar.

When the “Captain Trips” flu epidemic wipes out more than 99% of the population, the remaining few immune to the disease set out in search of other survivors, all the…