With Section 20 undermanned and under resourced after their perceived failure in Budapest, the team grow frustrated by the trivial nature of missions assigned to them by Whitehall. This all changes when the diplomatic convoy Sgt. Damien scott's shepherding across Kenya is hit by a Somali Warlord and British diplomat, Patrick Burton and his new Junior AttachÃ© Rachel Mcmillan are kidnapped. Also taken is a Libyan Civil Servant, Keemal who was attempting to flee Africa for a new life in the UK. Determined that Section 20's record not be further blemished, scott volunteers to single-handedly retrieve the hostages from Mogadishu, Somalia, where they are being held for ransom.
Meanwhile, Sgt. Michael Stonebridge struggles to adjust to his new role as an SAS Training Officer in the Brecon Beacons. Stonebridge and his wife Kerry's lives were shattered after her miscarriage, but both refuse to acknowledge that Stonebridge daily regrets his decision to leave Section 20.
Unable to ransom the Libyan Government for any hostage fee Waabri orders his men to kill Keemal, but the Libyan official offers Waabri a trade: his freedom in exchange for the contents of a cargo vessel sailing off the Gulf of Aden. Rachel and Burton, still manacled to a wall in Waabri's base can only look on as Keemal is freed to discuss his terms with the warlord.
Aided by consulate liaison carla and local apostle Sulaimani, scott is spirited through al-Shabaab occupied areas of Mogadishu into Waabri's zone. At Section 20, keen new recruit Sgt. Liam Baxter discovers that Keemal's real identity is that of Tafiq El-Gabhri - a reclusive Gaddafi insider with apparent interest in a ship that has just been hijacked by Somali pirates. scott is ordered by Mjr Oliver Sinclair, the new acting head of Section 20, to discover what's on board the vessel.
Back in the UK one of Stonebridge'S recruits, Jake Hanson is struggling with the Special Forces selection process. When Jake's brother, Craig Hanson, an old Special Forces mate of Stonebridge's, persuades him to give Jake another chance, Stonebridge supresses his better judgement, sending the recruit on a training exercise with live ammunition. Suffering from the effects of PTSD that he's kept hidden, Jake has a break down during the exercise, killing one of his fellow soldiers and wounding a second. As Jake trains his gun on 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 freedom, but when Waabri asks who the original buyer was - a shot rings out as Keemal is assassinated. From her elevated position hundreds of meters away mercenary Jessica Kohl inspects her shot. Their work done, she and her commanding officer, Carl Matlock sneak away undetected.
However scott's location is blown in the melee following Keemal's assassination. Whilst he flees the scene, the sheer number of Waabri's men on the ground proves overwhelming and after a gut-wrenching chase through the Mogadishu backstreets scott is captured!
With top brass refusing to provide further back up for the beleaguered team, Section 20 has two options: leave scott to rot a Somali hellhole, or call the one man they know will drop everything to lead a rescue mission.
Stonebridge and Richmond are on the first flight to Africa they can find, Stonebridge ignoring Kerry's pleas to stay with her and hear the results of the military enquiry into Jake Hanson's death.
In Mogadishu, Waabri tortures scott, convinced this American is attempting to infiltrate his lair and steal the case Keemal gave him. After a brutal beating scott is thrown into confinement with Burton and Rachel who are pleased to see him, despite their shared desperation.
Meanwhile, Matlock makes contact with Waabri - Keemal had no right to give Waabri the case: it wasn't his to trade, but Matlock is prepared to buy it back from the warlord. They arrange a handover - the details of which Section 20 are able to track.
After swimming to shore Stonebridge and Sgt. Julia Richmond lie, sneak and fight their way into Waabri's base, where a precision exfiltration is confounded by Waabri's numerous guards. Stealthy withdrawal blown, Stonebridge and Richmond shoot their way to the hostages - their escape is aided by two of Waabri's youngest guards who decide to leave with the group, but Rachel Mcmillan has gone missing...
Rachel has snuck back to search Waabri's private area for the case, when she's unable to find it, Rachel loads herself up with all the weapons she can carry and outside to point a handgun directly at scott and Stonebridge... Who is this woman?