Former Marine Frank Castle takes the law into his own hands while struggling to come to terms with his traumatic past.

A mysterious phone call forces Frank's hand. Meanwhile, Madani goes digging for suspects and Curtis delivers a message.

Frank skips the subtlety while interrogating Micro. Brutal memories of top-secret missions shed light on Frank's past.

Madani and Sam plan a delicate operation, Curtis tries to connect with Lewis, and Frank encourages Micro to get his hands dirty.

Frank and Micro go looking for answers from a reluctant witness. Madani and Sam learn of a looming investigation. Rawlins sees a ghost.

With Frank in bad shape, Micro calls on Curtis for help. Madani and Russo continue to mix business with pleasure. Lewis stands up for his rights.

Lewis struggles with the ramifications of his actions. Frank and Micro pursue another face from the past. Madani and Sam go bug hunting.

Russo opens up to Madani about his past, Sarah shares her concerns about her son with Frank, and a decoy operation takes a turn.

Following a deadly explosion, Karen lands in a bomber's crosshairs -- and Frank isn't happy about it. Meanwhile, Curtis makes a grisly discovery.

As danger knocks on Sarah's door, Frank takes his quest for vengeance to the next level with some help from an unexpected ally.

Frank makes a damning confession. A shootout leaves Sarah wondering what to believe. Rawlins goes in for the kill, once and for all.

As the authorities close in, an exhausted but unbroken Frank vows to put an end to the war that has consumed his life.