Gunner is the fifth episode of the first season of the television series The Punisher.
Frank and Micro go looking for answers from a reluctant witness. Madani and Sam learn of a looming investigation. Rawlins sees a ghost.
Dinah Madani wakes up bruised and battered, remembering the crash and Frank Castle.
At the hideout, Micro is annoyed at Castle's rescue of Madani because she now knows he is alive. Castle is angry at Micro for causing the crash in the first place. Castle leaves to go to the Lieberman Residence. Castle fixes Sarah Lieberman's headlight with Leo. Zach arrives with a skateboard that he did have that morning, and is angry to see Castle at the house again. Leo convinces Sarah to invite Castle to dinner on Sunday.
Arriving at the United States Department of Homeland Security, Madani is chastised by Rafael Hernandez for coming to work rather than rest and recover. Hernandez tells her that an investigation is pending; Madani does not tell him about Castle being alive. Madani begins to focus on Castle when Billy Russo calls to invite her for another drink.
Watching the Kandahar footage again, Micro asks who filmed it. Castle reveals that Gunner Henderson was the cameraman. Describing Henderson as a "hell of a soldier," he also says that Henderson knew that what they were doing was wrong.
At the CIA office in Langley, Virginia, Agent Orange, revealed to be William Rawlins, gives an orientation briefing to new recruits.
Investigating Castle, Madani calls in Karen Page for an interrogation. Madani enlists Sam Stein's help in tracking down other soldiers who may have been in the video with Castle, including Henderson. Stein refuses because it has nothing to do with their current case. Unknown to them, Rawlins had been listening to the conversation in the office via a listening device.
Madani leaves the office after him and admits to Castle being alive and saving her life. Madani and Stein are interviewed by the Office of the Inspector General, but neither mention Castle's involvement. Stein tells Madani that if they find nothing in a week, he will reveal the truth.
Page and Castle meet by the bridge. She tries to convince him to allow either her or Madani to expose the criminals he is hunting but he refuses. Castle does not want Page to become a target like his family.
At the field office, Rawlins is awarded the Distinguished Intelligence Medal by Marion James. James is being promoted to Director, and wants Rawlins as her Deputy Director as long as there are no skeletons in his closet that would come back to haunt them; Rawlins assures James that there are none.
Micro finds Henderson in a cabin completely off the grid. Castle and Micro head to the see him; Castle goes alone to find Henderson while Micro stays with the van. Finding the cabin, Castle is shot with an arrow. He convinces Henderson to talk with him and that he is not a threat. Henderson reveals why he filmed the Assassination of Ahmad Zubair: he had discovered that their superiors were using the bodies of dead soldiers to smuggle heroin back to the United States.
Alerted by Madani's interest in Henderson, Rawlins dispatches a tactical team to kill him. Castle and Henderson take out the tactical team, assisted by Micro who is spotting targets using a drone. Both Castle and Henderson are badly wounded. Rawlins – monitoring the operation remotely via helmet cameras on the soldiers – is shocked to discover that Castle is still alive.
At the Lieberman household, Sarah, Leo, and Zach wait for Castle to arrive for dinner but he does not show. Madani and Russo go on another date, and end up having sex.
In the woods, Henderson succumbs to his wounds but not before making Castle promise to bury him. As Henderson struggles to breathe, Castle staggers trying to reach the van, although he collapses and passes out before doing so. Micro finds him and carries him back to the van, giving him basic medical treatment. Castle wakes up during the drive back, and upon noticing his situation, remarks that there might be hope for Micro yet.