Hart to Hart (1979)

S2E20 Blue Chip Murder

When the Harts arrive back at their home, they are shocked to find it in disarray. As they begin to tidy up, they stumble upon a concealed hallway that leads to a hidden vault. Just as they explore this secret space with their friend Ida, the burglars return, intent on retrieving the municipal bonds stored inside the vault, trapping the Harts and Ida within.