Chuck finds a bug in the Buy More, and gives it to Casey. Neither of his handlers planted that particular bug. Fearing Chuck's cover has been exposed, the government prepares to bring him in. While the agents try to find the culprit, Chuck tries to find an engagement ring Devon asked him to hold until Devon can propose to Ellie.
Team Chuck recovers some equipment. They're told it's the last component for the new Intersect, which will be brought on line. Chuck is relieved at the prospect of returning to a normal life and asks Sarah out. Meanwhile Casey receives orders that cause some inner conflict.
Fulcrum has intercepted an update for the new Intersect. The chip has data that could expose Team Chuck. Bryce and Sarah must pose as a married couple to get the chip back. Chuck's jealousy causes some problems, but Sarah's decisions endanger the mission, and forces Chuck to make some decisions of his own. Meanwhile the Buy More crew must deal with bullies from a sports store.
Chuck flashes on a person at the Buy More, he's a nuclear terrorist looking for Jeff. Chuck hangs out with Jeff to discover why he's being targeted. The team will need Jeff's help prevent a nuclear attack.
Chuck goes to a corporate office and encounters his ex-girlfriend, Jill. He tries to avoid her but they catch up. Later he gets a flash on one of Jill's associates. Now he must reconnect with Jill to determine her involvement. The Buy More crew must pass CPR certification.
General Beckman finds intelligence that suggests Guy had a list of Fulcrum Agents. She orders the team to find the list. This causes some problems when Chuck tries to rekindle his romance with Jill. When Jill is endangered, Chuck is forced to make some difficult decisions, and the team is not prepared for what comes next.
Casey and Sarah discover Jill's secret and race to warn Chuck. Now the team tries to lay a trap for Jill, but Jill's not alone. Chuck will find out more about their break up, and he'll have to decide if they should try to rekindle their romance.
The team encounters a rogue agent, Casey's former Sensei. He's been recruiting former students and getting them to steal weapons and secrets. Ellie must face Awesome's parent who are overly enthusiastically planning the wedding. At the Buy More, everyone competes to be the Employee of the Month.
Sarah's father comes for a visit. His latest con involves a sheik with possible terrorist ties. When the sheik shows up, the Team must help her father to pull off the con. Meanwhile Anna makes a suggestion that forces Morgan to consider making more mature decisions, is he ready?
A car crashes into the Buy More, everyone inside, including Ellie and Devon are taken hostage. Chuck does his best to protect everyone. The real goals are not evident, and it will lead to some very hard choices.