A woman finds a baby Kaprosuchus dinosaur in her house. Not knowing what it is, she flushes it down the toilet. Five years later the creature has grown into an adult and lives on homeless people down by the docks.
Connor (Andrew Lee Potts) and Abby (Hannah Spearritt) find out that, since they’ve been away, policy at ARC requires that all new field employees must have a military background. This means they are both out of a job. With Abby’s zoological background she is offered a minor position taking care of the animals in ARC’s menagerie. These are the animals they were not able to return to their own time. Jess (Ruth Kearney) offers to let Connor stay at her place until he can get situated somewhere else.
While on the internet looking for apartments, Connor finds a website called “Creaturesightings.com”. On it he sees a report by his old friend Duncan (James Bradshaw). When he visits Duncan, Connor finds him obsessed with the missing homeless people and believes that there is a government conspiracy hiding the creatures. Duncan takes Connor down to the docks. They find a mangled body. Connor calls Abby and verifies that there are no anomalies at present.
Abby heads down to the docks to help Connor. Matt (Ciaran McMenamin) notices Abby acting funny and follows her. Jess notices Matt acting funny. By the time Matt gets to the docks the Kaprosuchus attacks. Jess sends Becker (Ben Mansfield) and a tactical team. Soon the entire team is tracking down the creature.
Episode 2 of season 4 features a Kaprosuchus. Kaprosuchus or Boar-Crocodile was a genus of crocodyliform from the Cretaceous period. They were carnivorous and able to swim similar to a crocodile.
The Bio-tag Identifier was an identification and security device worn on the wrist. It attached to the wrist in the same way a slap wristband worked. Each Bio-tag was linked biometrically to the individual. With it the individual could open doors in ARC by passing it over a sensor next to each door.