When flight attendant Cassie Bowden meets handsome, beguiling passenger Alex Sokolov on the way to Bangkok, she decides to spend an extravagant, very drunk night with him.

Rattled by her own lies and under pressure from the FBI, Cassie goes against her lawyer best friend Annie's advice to lay low and tries to track down Alex's mysterious business associate Miranda - with bizarre and shocking results.

Upon landing in Rome, Cassie deals with her sudden feelings of loss, and Megan confesses that she has secrets of her own. Back in New York, Cassie doubles down on finding Miranda by unceremoniously crashing Alex's memorial service.

After literally piecing together evidence from Alex's family home, Cassie follows the paper trail to a private jet service. But she also has to juggle a visit from her brother Davey and his family, unearthing more of her 'unconventional' childhood.

With fresh trauma, Annie's job on the line, and the FBI closing in, Cassie enlists Max in a plan that involves breaking and entering, computer fraud, too much vodka, and a Hello Kitty flash drive. Meanwhile, Annie's work life goes very dark.

Her friendship with Annie is falling apart and there's danger everywhere, so Cassie runs from anything related to Alex and spirals into an alcohol-fuelled escapade with Buckley that ends in a jail cell meltdown. Also, Megan's secrets threaten to come to light.

Finally face-to-face with Miranda, Cassie's ideas about Alex and everything that's happened since Bangkok are turned upside down. And in a cheap motel, Megan's whole life implodes.

After the shocking reveal of Alex's killer, Cassie and a surprising new ally devise a plan to fix everything that unfolds disastrously in Rome. Meanwhile, Annie gives the FBI evidence and Megan comes clean.

Cassie is living her best life in Los Angeles, has a supportive new boyfriend Marco… and moonlights as a CIA asset. But when her latest assignment inadvertently makes her an eyewitness to a murder in Berlin, Cassie becomes entangled in yet another international mystery.

Cassie sets out to find the mystery woman who's been impersonating her, and immediately suspects new flight attendant Grace. Annie prepares for an interview at a progressive LA-based law firm, and Marco and Davey attend Cassie's AA meeting to celebrate her sobriety.

Convinced that a cryptic text bears clues to Megan's location, Cassie jumps on a plane to Reykjavik and visits haunts from seemingly better times. Meanwhile, Shane grows increasingly suspicious of Cassie's erratic travels.

After learning the cryptic text was actually meant to send her elsewhere, Cassie tries to get Megan safely out of Reykjavik. Back in LA, the Diazes interrogate Annie and Max, and, later, Cassie fears she's being framed for murder when two bodies are found in Echo Park.

Finding her own file in Benjamin's office, Cassie seeks assurances from Shane during their annual flight attendant safety training. Max attempts a high-tech hack to track down the Diazes, and Megan searches for a lockbox that holds evidence against the North Koreans.

While travelling to New York with Davey to pay their mom, Lisa, a visit, Cassie faces hard truths about her path to sobriety. Meanwhile, Megan attempts to reconnect with her reluctant family, who are wary of the web of legal troubles she's entangled them in.

Cassie runs down a lead in the string of murders – which points to her as the key suspect. Encountering a man with ties to the N. Koreans, Megan grows concerned for her family's safety. Max decodes another clue, leading to a cat-and-mouse chase at the Santa Monica Pier.

Still in shock from the events at the pier, Cassie manages to get even closer to connecting the dots in a far-reaching conspiracy. After arriving in LA, Megan looks to make amends with Shane and start a new chapter in her life.