When Elliot's drug shipment is spiked, rocking the Gangs and causing hundreds of deaths, the hunt is on for who is responsible.

Sean, Billy and Cornelius make a drastic attempt to reclaim London, while Luan tries to take revenge and Elliot seeks answers.

Elliot's investigation puts him on a direct collision course with the Mayor. Marian decides whether to reunite with her family.

Luan takes drastic action to defend his family. Elliot uncovers a piece of the spiking mystery. But will it cost him everything?

As Lale faces a difficult choice, Asif is made an enticing offer and Marian discovers something that could impact her family.

A showdown between Elliot and Zeek leads to a shocking discovery. Has Elliot been looking for answers in the wrong places?

Elliot places his trust in a surprising ally to uncover the truth. Ed meets an old contact, as events build to a Gangs showdown.

The extent of the conspiracy is revealed. Elliot's past and present collide and the Gangs take revenge, changing London forever.