Maisie takes a risk to rescue Georgie and Milan from the collapsing house. When they discover that children from the village have been taken to be sold as slaves in Kathmandu they set off to free them.
Still grieving and heartbroken from the death of Elvis Harte, Lance Corporal Georgie Lane (Michelle Keegan) is sent to Nigeria on a training mission, alongside 2-section. Working as part of the British Army's effort to help train local forces in the fight against terror, Georgie throws herself into work helping to train local medics, as well as overseeing a local women's health initiative. However, whilst 2-section work hard helping to equip the Nigerian Army, everyone is soon put on edge when they encounter a local crime boss and a seemingly ruthless band of ...
Georgie can do little as the Boko Haram rebels beat the Nigerian members of the group. She finds the unlikeliest of allies when the local crime boss is revealed to be an undercover special forces operative.
Now in Belize for a jungle training exercise Section 2 members quickly get into a row with natives at a bar. Split into two teams by local commander Mendez the aim is to locate and return to base a mythical injury victim. James' group beats Georgie's but he is shot in the leg by drug-dealing bandits and Georgie, helped by local boy Ezra, attempts to bring him back to safety, discovering a truth from him as they try to escape from the drug-dealers.
Back at base the section receives a weak signal from James' tracker and Bones arrives with his team to locate him and Georgie. The endangered couple are helped by Ezra, who takes them to the safety of a cave, where James admits to a responsibility for the death of Elvis. The pair are rescued but not without innocent casualties.
With James recovering from his injuries Bones takes charge as the unit moves to Bangladesh to help Rohingya refugees fleeing persecution in Myanmar. Georgie and young Jason Curry - nicknamed Ruby - assist Inspector Chowdhrey and his wife Bharsha at their make-shift hospital, which is short of supplies as more refugees flood the camp. However danger is present in Bangladesh when a suicide bomber strikes, claiming one of the section as his victim.
Following Bones' death James returns and security checks are in force. Georgie is puzzled to see Chowdhrey doing business with a man without Bharsha's knowledge and, aware that drug smugglers are using the refugees, she tells James. It becomes apparent that Chowdhrey is in league with the smugglers and was the bomber's target, especially when he disappears. However James has his own crisis.
A cholera outbreak adds to the section's problems, stressing out Georgie and Ruby. Chowdhrey is arrested but refuses to give his captors any information until Georgie asks for Barsha's intervention. Then Georgie and Maisie are attacked by gunmen who kidnap the Chowdhrey's young son.
Georgie is caught in the crossfire when another attempt is made on Inspector Chowdhrey's life, forcing her to re-examine her feelings for her captain. With Chowdhrey's son Sumon still missing, Georgie persuades James to call in special forces. A daring mission is conceived, but 2 Section find themselves in a deadly shoot out with the drug gang to recover Sumon and halt the yaba trade.