The Relic

Whitney confronts the ship captain and asks him to remove the cargo bound for Chicago. The captain refuses to delay the voyage, so Whitney sneaks aboard the ship. Unable to locate his cargo, he cries out, drawing attention.

The cargo ship finally arrives at Lake Michigan with its crew missing. Police boards the vessel to begin a search for clues and the missing cargo. The eerie scene hints at a deadly mystery behind the voyage.

D'Agosta and Hollingsworth inspect the ship's bilge and discover dozens of corpses. The discovery confirms a murderous event aboard and raises the stakes of the investigation. The team starts linking the shipboard deaths to other recent mysteries.

Margo Green arrives at the Field Museum and learns that coworker Greg Lee is vying for the same research grant he already secured. The rivalry adds professional tension to the unfolding crisis. She prepares to examine Whitney's crates later that day.

Margo and Albert Frock examine Whitney's crates and find them empty except for a bed of leaves and a stone statue of the Kothoga. She notices a fungus on the leaves and sends it for analysis, while the remaining leaves are incinerated. The discoveries hint at a dangerous biological element at work.

That night, security guard Frederick Ford is murdered by an unseen predator within the museum. D'Agosta suspects a connection to the shipboard deaths and the Whitney crates. The killer appears to be still inside the museum.

D'Agosta orders the museum closed to allow a full search, believing the killer remains inside. Mayor Robert Owen and the museum's security head push to proceed with the upcoming exhibition. The public display goes on under heightened tension.

Margo analyzes the fungus and discovers concentrated hormones found in several animal species. In the container with the leaves, she finds a mutated beetle with mixed insect and reptilian DNA. She crushes the mutant, suspecting a link to the killings.

Ford's autopsy reveals that his hypothalamus was removed, mirroring the method used on the ship's crew. The pattern strengthens the theory that a single predator is responsible for all the deaths. The investigators connect the museum events to the earlier voyage.

In the museum basement, officers encounter a mentally ill ex-convict and kill him. They also find Ford's wallet and an identity tag from one of the ship's crew, prompting the belief that the suspect is dead. The case is treated as closed for now.

D'Agosta tightens security and keeps all areas sealed off except the main exhibition hall. The opening proceeds, but panic erupts when a murdered officer's headless body falls into the crowd. Alarms and security systems complicate the event.

The Kothoga, a terrifying chimeric beast, penetrates the lab and attacks D'Agosta, Margo, and Frock. They barricade a steel door to slow its advance while they search for a way to stop it. Frock theorizes that the leaves feed the creature and hopes to cut off its food supply.

D'Agosta uses the leaves to lure the Kothoga away from the coal tunnel, allowing trapped guests to escape. CPD officer Bailey and a guest are killed during the pursuit. The beast returns to the main hall to continue its hunt.

Margo's computer analysis reveals that John Whitney is the Kothoga, mutated after drinking the tribesmen's soup. The revelation reframes the events as the actions of a single transformed predator. The killer's origins are finally understood, though the danger remains.

The Kothoga bursts into the lab, chasing Margo and D'Agosta. Margo triggers an explosive fire and incinerates the beast by trapping it inside a maceration tank. Dawn arrives as police break in and rescue Margo.