The negotiator

Former police officer Tia quit the Met years ago when she failed her exam to become a negotiator, her dream job. But when a peaceful climate protest at a London museum turns deadly, and one of the radicalised group members takes Tia and others hostage, she realises this is her chance to prove she has what it takes. Only not everyone gets out of the siege alive. Three years later, Tia discovers that the surviving hostages are being harassed by an anonymous person, leading one of them to take their own life. Refusing to have another death on her conscience, Tia begins to investigate. But Tia was a hostage that day too - and now she's a target.