Myka is surprised to answer her phone and hear H.G. Wells's voice on the other end! Helena, working as a forensic scientist in Wisconsin, sees a man run into the police station and confess to a crime he'd been cleared of, only to transform before her very eyes.
Helena is trying to build a new life for herself with her boyfriend, Nate, and his young daughter, Adelaide, so she doesn't want to get involved in the investigation. When Myka pleads for her help, she obliges, and they find that it was the arresting detective who used the artifact that made the man turn Cro-Magnon
The detective, Briggs, knows something is up with Helena and visits her home to intimidate Nate. He uses the artifact, a hyena jawbone, to strike fear into Nate that's strong enough to transform him into a cave man. Myka and Helena arrive in time to bag the artifact and save him, but soon Briggs kidnaps Adelaide, and the stakes grow higher!
Claudia is begrudgingly sharing her workload with Abigail. The warehouse, which Artie informs them automatically expands, is shaking and quaking because of a new acquisition that keeps the expansion from happening. They have to neutralize that artifact, but getting close to it is going to be a problem.
Claudia and Jinksie make a goo shooter that should reach up to the roof of the building, but in another electric burst, the warehouse shoots a bolt of lightning that breaks the ladder Steve's on and injures Artie.
Claudia and Abigail must go on alone, and Claudia is forced to confess that she thinks the warehouse is mad at her and has been zapping her behind. She hid this information from Abigail because, y'know, it sounds crazy pants - and she thinks that if the Regents know, they won't let her be the Caretaker. Abigail suggests that maybe the warehouse has been trying to get her attention.
Claudia summons the courage to head into the eye of the electrical storm, shoots the goo rocket into the air, and their problems are solved! Now to get Steve down from the precariously high heights...
Myka feels responsible that she dragged Helena and her new family into this, so when Briggs calls and tells Helena to bring the jawbone in exchange for Adelaide, Myka goes on her own.
Helena and Pete are close behind, and soon discover that the district attorney is working with Briggs to serve out vigilante justice. The downside of the artifact makes the D.A. hideously violent, and the three agents just barely manage to re-bag the artifact and cuff the criminals.
They return Helena home to her loved ones, and make her promise to live a full and happy life, with as little contact with artifacts as possible.