Artie stands trial before the Regents for Leena's death and is found innocent, a verdict that does not sit well with him.
Pete tries to get Claudia's mind off of the situation with Artie by taking her on a ping in the woods, where a victim was buried alive. When they find a second body killed in the same way, they discover another connection - the logo of a defunct eco-terrorist group called The Last People On Earth.
Artie is fighting his way through his grief the only way he knows how - alone - and trying to do all the things Leena used to do around the warehouse, including shelving new artifacts. Artie's methods aren't airtight, however, and the porthole artifact that he shelves sets off the entire row, including da Vinci's gargoyle!
Only one member of the Last People On Earth was tried for the crimes of all, and he recently died in prison. Two others are the recent victims, and the final one, Autumn, is the head of a local environmental group. If things keep going the way they're going, she could be the next one on the hit list.
Forest Ranger Evan Smith - actually the brother of the LPE member who died in prison - has been using a lantern artifact to kill his targets. He gets the drop on Pete and Claudia, and manages to abduct Autumn and take her to a nearby logging site, owned by Mr. Lockheart, the man who was targeted by the LPE when they were active.
Evan wants to make Autumn watch as he destroys Lockheart and his logging site - Autumn turned her boyfriend, Evan's brother, in to the Feds because he was turning their mission violent. Claudia manages to blast him with the Tesla and knock the lantern out of his hands. Pete lowers her down the side of the cliff to where the lantern fell and she bags it.
Back on solid ground, Claudia bonds with Autumn over the woes of doing something tough to save someone you love. Knowing that someone else went through it before helps put perspective on her situation with Artie.
Artie, Jinks and Myka must trap the gargoyle and save the warehouse. Artie lets Jinks use the really cool feng shui spiral that sorts the artifacts - the porthole was improperly shelved because the spiral was reading Artie's sadness instead of the artifact's essence of "indescribable beauty."
Claudia returns home and gives Artie the hug he deserves. He utters a simple "thank you" and then turns to watch the signature video statement that Leena made when she joined the Warehouse team. Seeing her state clearly that she wanted to be a part of this even though it was perilous allows Artie to let go of a little pain.