The episode opens with Shaw attempting to steal the Mask of Alexander from a museum, only to be trapped in the vault with rapidly depleating oxygen. Shaw calls upon Chuck for help. Back at the Buy More, Chuck is busy flirting with Hannah when he gets the important Nerd Herd call to fix the crashed servers at the museum (thanks Casey!). Chuck heads off, and Hannah who was promises to come along on the next Nerd Herd call, sneaks along. The two of them manage to bring the server back and free Shaw in time to save him. This also lands the two of them a gig at the Mask's unveiling. Perfect for helping Shaw steal in in order to get whatever the ring hid in there.
At the unveiling party, Shaw and Sarah pose as a couple (while Shaw flirts heavily with her), Casey does surveillance, and Chuck and Hannah work from the control room. After kissing Hannah, Chuck flashes on a Ring operative, Nikos (Henri Lubatti), and runs to Sarah and Shaw. When Chuck finds out Nikos knows Shaw's face, he sends him home, and Sarah and Chuck take over the mission (all while a jealous Hannah watches on surveillance). After a nerve racking action sequence, Chuck and Sarah steal the Mask and replace it with a fake, but not before the ring is able to see who they are on surveillance footage.
At the Nerd Herd desk, Nikos, posing as the museum curator, calls and requests for Hannah to fix their server. They kidnap her and call Chuck and ask for him to return to the mask in exchange for her life. Meanwhile, Sarah and Shaw attempt to figure out what the Mask holds and they accidentally reveal and poisonous gas. Now, Chuck must get the antitode and save Hannah. Casey heads in with him and they bring another fake Mask and put in a smoke bomb to replace the gas.
During the final showdown, Chuck gases Nikos, who reveals the antitode is hidden in a vase in the museum. Chuck knocks him out and locates the vase. Shaw manages to bring Sarah, who's suffering from the poison worse than him, in to the museum where Chuck gives them the antitode. He then goes and rescues Hannah. During their poisoning, Sarah reveal to Shaw that she likes him and in the end they end up hooking up while Chuck and Hannah do the same.
At the end of the episode, we cut to the ring HQ where they announce they want Shaw dead. Big shock.
Meanwhile, throughout the episode Ellie and Morgan spy on Chuck to figure out his secret life. In the end, they walk in on Chuck making out with Hannah in the home theater room and think that's what the big secret Chuck has been hiding.