Mission: Impossible (1966)

S7E20 The Pendulum

Gunnar Malstrom heads the Pendulum, a covert terrorist organization plotting Operation Nightfall against the U.S. government, prompting the IMF to step in and apprehend him. Casey is romantically involved with Malstrom and brings him to World Resources Ltd., an IMF front posing as a competitor, where she offers him a job if he forsakes Pendulum. The IMF employs a concealed polygraph to uncover Pendulum's scheme to assassinate a general, but they remain unaware that the deed has already been done. As Pendulum intends to detonate a bomb targeting the Chiefs of Staff, Jim attempts to alert the fake general, who invites him to the meeting. With the help of a hidden transmitter, the IMF learns of Pendulum's actual plan, and Jim manages to defuse the bomb just in time.