When her teenage son is jailed for murder in Bulgaria, flight attendant Jo enters a murky world of drug smuggling and will stop at nothing to save him.
After a fight outside a bar in Sofia, 19-year-old Sonny Conran is convicted for the murder of a member of an infamous criminal family. His mother Jo, a flight attendant, is blindsided by a threat to her son's life, but is then told she can keep him safe by agreeing to take on an additional role at work - as an international drug smuggler.
Left with no choice but to continue Cormac's international drug runs, Jo turns to her ex, Dom, for help. Following a close call with the police, Jo is forced to quickly secrete heroin in the airport, but it goes missing - and Cormac gives her 24 hours to get it back. Meanwhile, a rattled Dom attempts to flee with his family. But after failing to convince wife Mel they need a holiday, he turns to Jo for comfort and they vow to fight back.
Jo rushes to Sofia when Sonny is stabbed in prison. While keeping vigil at his bedside, she gets caught up in a second attempt on Sonny's life and struggles to accept Cormac's claims of non-involvement. Having enlisted the help of his former police partner, Shana, Dom is told that the Met have zero intel on Cormac. Dom deduces that he must be a small-time bully with no real connections, but then witnesses Cormac murdering a man on the street. Meanwhile, Jo returns home to a surprise visitor who delivers some shocking news.
Dom warns Jo that Cormac is extremely dangerous but she ignores his advice and follows him to a meeting with an unknown boss. A veiled threat makes Mel suspicious and a new witness comes forward in Sonny's defence - although things do not go as expected at the appeal hearing. Jo is told to run - but instead, she and new ally Kayla come up with a new plan.
After stealing the heroin and money, Jo realises Cormac is also being blackmailed, so they collude to get out for good. Smuggling more heroin, they sell it on, while Cormac puts things in place for Jo's escape. Kayla gives birth, and Shana reveals to Dom that Cormac's boss is Anton Marquis - a senior police officer.
Jo demands answers and finally uncovers the truth in Sonny's case. She and Cormac execute their escape plan, though she remains uneasy as to whether he can be trusted.
