Kate experiences the force of nature that is Tully when they meet as teens, at their first journalism jobs in 1982 and over a PTA crush in 2003.

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.

Tully's lie threatens the pair's friendship. Kate feels stressed over huge life changes. A treasured gift leads to a gut-wrenching goodbye.

Tully's mom disappoints her again and again, and Kate's boozy night with her best friend and their coworkers causes awkwardness, accusations and hurt.

Vows are made and hearts broken as Kate navigates her long-strained relationship with her brother, and Tully grapples with compromise and commitment.

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

A teen magazine. A political investigation. A secret message. Shocking revelations lead to major questions for Sean, Tully and Kate.

As Tully's career takes off, uncomfortable encounters at work keep throwing her off track. Johnny's behavior causes concern among his loved ones.

While celebrating their own freedom on Independence Day, Tully and Kate learn time and again that relying on each other may not be so bad after all.

For the first time in decades, Kate and Tully experience a year apart — but can they handle major life events without each other?

Kate has often felt invisible next to Tully through the years. But amid major changes, Kate realizes she may need her best friend by her side.

Kate and Johnny's loved ones gather for two very different celebrations. Tully gets tangled in a romantic dilemma, and Kate feels the weight of a secret.