On a special day for the Mularkey family, Tully reflects on decades of work, love, grief and joy alongside her best friend. Kate faces the unknown.

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.

Tully, Johnny and Marah try to find ways of coping after Kate's revelation. In the 1980s, Johnny wrestles with another piece of overwhelming news.

A bridal shower stirs up resentments and memories, an awkward encounter leads to a life-changing question, and a tragedy shakes teenage Kate's world.

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

From bra-stuffing to breastfeeding, Kate experiences several bumps in the road on her journey from a self-conscious teen to a first-time mother.

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.

Johnny and Kate reminisce at a party about a life-changing kiss in the same newsroom, 20 years earlier. Tully gives Danny advice on his love life.

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

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.

The BFFs catch the attention of a school bully. Kate attempts to move on. Tully faces choices that could change her life personally and professionally.

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.

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.

Tully attempts to face unresolved loose ends from her past. But her choices lead to a potentially unforgivable mistake that impacts Kate's life.

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

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

Trying times bring Kate and Tully together as they contend with an overbearing grandma, a pesky new intern and an ex-husband in distress.

From a double date in 1975 to Tully's search for her father in 2004, Tully and Kate attempt to take charge of their futures — but fate has other plans.

Kate learns that dealing with an ex is always tricky, no matter the decade. After years of never saying sorry, Tully struggles with accountability.

A traumatic assault. A hidden romance. A signed consent form. Secrets both shared and unspoken test Kate and Tully’s friendship over the years.

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.

Over the decades and several road trips, Tully and Kate strengthen their bond and forge new relationships while occasionally testing them.

Sneaking out to a school dance, breaking a news story and enjoying a hip-shaking night on the town, Tully and Kate whirl through life together.

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

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.