<P> "Chuck Versus the Gravitron" is the eighth episode of the second season of Chuck . It was broadcast on November 24, 2008 . Chuck, Sarah and Casey are shocked to discover that Chuck's girlfriend Jill is a Fulcrum agent in search of the Intersect . In the wake of his disbelief, Chuck is asked to use his relationship with Jill to get to an agent called Leader . </P> <P> In 2003 Chuck and Jill sit atop a Ferris wheel as Chuck tries to ask Jill out . Back in the present, Sarah and Casey worry about Chuck after finding out Jill is Fulcrum and that she has Chuck . Jill is in bed with Chuck at a hotel . When Jill leaves to take a shower Chuck flashes on her cell phone and realizes she's a Fulcrum agent . </P> <P> Back at Chuck's apartment, Chuck kisses Jill goodbye, pretending absolutely nothing is wrong . Inside his sister's house, Chuck feels sorry for himself, while General Beckman gives tells them the flash in Jill's room referenced an agent called Leader . Chuck must stay close to Jill to find him . </P> <P> Chuck and Jill go to a carnival where Jill tells Chuck she's Fulcrum and they run into Leader, who Jill betrays to protect Chuck . However, Leader escapes and Jill is captured . </P>

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