Open Grave (2014) Timeline Explained – Every Event in Order

The amnesia was caused by Jonah's experimental vaccine. The video footage reveals that the vaccine, designed to fight the infection, comes with a sinister side effect: temporary amnesia and a deathlike state. John, Sharon, Lukas, Nathan, and Michael were all part of Jonah's medical team working on the cure, and they were infected during the clinical trials.

Foreshadowing: Earlier scenes show the group having random skill flashbacks, familiarity with firearms and languages, that hint at their professional backgrounds.

• amnesia
• vaccine
• memory loss
• Jonah
• medical team

The mute woman is revealed to be immune to the devastating virus. Sharon's final letter explicitly states that the mute woman possesses an extraordinary immunity, making her humanity's potential savior. This is why she was able to survive unscathed among the infected.

Foreshadowing: Throughout the film, the mute woman navigates dangerous situations without fear and shows no reaction to the infected, hinting at her immunity.

• mute woman
• immunity
• virus
• cure
• salvation

The calendar marking the 18th represents the expected date of military rescue. Nathan recalls this date as critical, and the group prepares for evacuation. However, when the military arrives, they turn hostile and begin hunting down survivors instead of rescuing them.

Foreshadowing: The ominous calendar appears early in the film, building tension about an impending event the characters dread.

• calendar
• 18th
• military
• rescue
• date

Jonah is Dr. Jonah Cooke, the scientist who developed the vaccine. The video footage shows him conducting medical experiments, and documents in the forsaken car confirm he was leading the medical team attempting to stop the pandemic that transforms humanity into violent creatures.

Foreshadowing: Jonah's fearful demeanor and the group's protective behavior toward him early on hint at something hidden about the boy.

• Jonah
• Dr. Jonah Cooke
• scientist
• vaccine
• medical experiments

The military arrives on the 18th but shifts from rescue to hunting survivors. Their sudden brutal turn appears deliberate, hunting down any sign of life with cruel indifference, though the exact reason remains unclear. This betrayal forces Jonah and Sharon to flee for their lives.

Foreshadowing: The earlier calendar and tension around the 18th foreshadow this catastrophic shift in the military's behavior.

• military
• hostile
• attack
• survivors
• betrayal

Sharon's letter contains crucial survival information: it reveals the mute woman's immunity to the virus and outlines essential details for their escape. The letter represents hope for humanity's future through the mute woman's unique immunity.

Foreshadowing: Sharon urgently writes the letter just before the horde attacks, emphasizing its life-or-death importance.

• Sharon
• letter
• mute woman
• immunity
• survival

Lukas attacks Jonah because the video footage reveals that Jonah conducted medical experiments on the group, causing their amnesia. The discovery that Jonah is responsible for their lost identities and the experimental vaccine sparks Lukas's violent rage.

Foreshadowing: Tension between Lukas and John escalates earlier, with Lukas viewing John as an outsider.

• Lukas
• attack
• Jonah
• video
• rage
• revenge

Michael is killed while investigating distant cries. He discovers a wounded man trapped in barbed wire, but the injured man overpowers and kills Michael before Jonah can intervene, marking one of the group's early losses.

Foreshadowing: Michael's curiosity and tendency to wander off were established earlier in the narrative.

• Michael
• death
• killed
• barbed wire

Jonah survives by feigning death. He returns to the body pit, injects himself with the life-saving vaccine, and enters a deathlike state, similar to his earlier self-induced coma, so the military won't identify him among the corpses.

Foreshadowing: Jonah had previously used this same method to survive after infecting himself with the virus.

• Jonah
• death
• vaccine
• body pit
• survive
• military

Nathan is killed by the infected horde while attempting to reach the military rescue. Despite his brave effort to venture into the desolation, he is overwhelmed and dies, leaving Sharon and Jonah devastated by his loss.

Foreshadowing: Nathan's determination to reach the military and recover his memories drives his fatal decision.

• Nathan
• death
• infected
• horde
• military