The case starts in chaos, well it ends in chaos. Basically, the episode opens with a flashback. The team is sent to mandatory evaluation after doing a horrible job on a case. In order to maintain their partnership with Homeland Security, everyone will have to pass.
At the museum, Walter decides to prove the painting in a fake by ripping it with a knife. This is not the best plan, but thankfully, an FBI Agent gets the team back on the case.
The theory is that the painting was forged by a machine, and Agent Gallo brings the team to someone who he thinks can lend some expertise - Hetty Lange. It's a Scorpion and NCIS: Los Angeles mini-crossover.
Toby and Sylvester narrow down the suspects from a company called Galactic Toys. The suspect owns up to being hired to copy a painting, and he gives up the person who hired him.
Even though Agent Gallo tells the team to wait for some intel, Walter decides that the team is going to infiltrate a fancy fundraiser. Sadly, the team comes up empty on the painting front.
On the plus side, the team cloned the rich guy's phone, and that's when they learn the curator's connection. Now all that's left is to get Agent Gallo to catch the guy with the painting in the trunk. It's a perfect plan. Agent Gallo has arrested the guy, and then the car goes up in flames with the painting still inside.
Luckily for Team Scorpion, they pass their psych evaluation, and they even attend Ralph's school's Halloween party.