Sergeant Damien Scott is transporting Keemal, a Libyan Civil Servant, across western Kenya, along with the British diplomat Patrick Burton and his junior attaché Rachel McMillan. They're attacked by a group commanded by a Somali warlord and the passengers, minus Scott, are taken hostage. Scott volunteers to single-handedly retrieve the hostages from Mogadishu, Somalia, where they are being held for ransom.
The warlord, Waabri, doesn't believe he will be able to ransom Keemal for any hostage fee from the Libyan government, so he orders a child soldier to kill him. Desperate, the Libyan official offers Waabri a trade: his freedom in exchange for the contents of a cargo vessel sailing off the Gulf of Aden.
Aided by a British consulate liaison and a local apostle, Scott is spirited through al-Shabaab occupied areas of Mogadishu into Waabri's zone. At Section 20, new recruit Sergeant Liam Baxter discovers that Keemal's real identity is Tafiq El-GabhriI - a reclusive Gaddafi insider with apparent interest in a ship that has just been hijacked by Somali pirates. Scott is ordered by Major Oliver Sinclair, the acting head of Section 20, to discover what's on board the vessel.
Back in the UK, Sergeant Michael Stonebridge tries to adjust to his new role as an SAS training officer. One of Stonebridge's recruits, Jake Hanson, is struggling with the Special Forces selection process. When Jake's brother, Craig, an old Special Forces friend of Stonebridge, persuades him to give Jake another chance, Stonebridge supresses his better judgement and sends the recruit on a training exercise with live ammunition. Suffering from the effects of PTSD, Jake has a breakdown during the exercise and kills one of his fellow soldiers and wounds another. As Jake trains his gun on a third soldier, Stonebridge is forced to intervene and shoots Jake dead on the spot.
In Mogadishu, Scott has tailed Keemal to his meeting with Waabri, where the Libyan hands over the cargo from the boat: a small case. Keemal has secured his own freedom, but when Waabri asks who the original buyer was, Keemal is assassinated by a sniper's bullet. In the ensuing melee, Scott's position is revealed and he's captured by Waabri's men.
With top brass refusing to provide further back up for the beleaguered team, Section 20 has apparently hit a dead end, forced to leave Scott to rot a Somali hellhole. But Sergeant Julia Richmond calls the one man she knows will drop everything to lead a rescue mission. Stonebridge ignores his wife Kerry's pleas to stay and takes the first flight to Africa he can find.
Carl Matlock, the mercenary whose sniper Jessica Kohl took out the Libyan, makes contact with Waabri, offering to buy back the case. They arrange a meeting, the details of which Section 20 is able to track.
After swimming to shore, Stonebridge and Richmond fight their way into Waabri's base. They reach the hostages just as they're about to escape and are joined by two of Waabri's young guards.
As the group prepares to move out, Rachel sneaks back inside to search Waabri's private area for the case. When she's unable to find it, she loads herself up with all the weapons she can carry, shoots one of Waabri's men, and leads the group towards an exit. Scott and Stonebridge exchange looks that ask, "Who is this woman?"