Following an urgent trip to the Arctic, a scientist and his friend are quarantined with an illness that soon escalates into something sinister.

Michael continues to prowl for victims while Luther struggles with a traumatic loss and painful accusations. Also, Kaylee makes a connection.

The government struggles to contain and understand the outbreak. Kaylee interviews Luther's ex-wife while Danika pays her sister a visit.

Luther pleads with the DNS to bring in Michael alive, but other pursuers have less peaceful intentions. Meanwhile, Danika's urges grow stronger.

As Michael and his followers settle into new accommodations, a tough-talking general takes control of the DNS. Also, Luther witnesses a brutal act.

Desmond's health worsens, forcing Luther down a dangerous path. Later, Luther receives a surprising offer and Michael lays down the law.

Luther connects with a Washington insider who has a plan to keep society from collapsing. Ava sets out to get proof of the DNS internment camps.

Luther's testimony rattles a few cages. Desmond and Amélie investigate an unsettling noise. Danika and Michael hit the town.

An official truce is announced but complications quickly arise, threatening the lives of humans as well as Bloods.