Highlander: The Raven - Season 1 Episode 16 The Frame

Nick is hired to return a painting by Sir Trevor, and invites Amanda along so she can get a taste of "doing good." The picture is mysteriously restolen as they leave, and Amanda's past raises the suspicion of the local police. It turns out that another Immortal, Jade, patterns herself on Amanda and likes to one-up her. The two have been rivals for centuries. Things get further complicated when Jade tries to sell the picture, and Nick and Amanda manage to recover it. It turns out that Trevor had a fake picture stolen for the insurance, and plans to secretly sell the original. The duo's return of the picture screws up his plans, but since the fake is in the gallery they'll be in trouble as well if Trevor reveals he got a fake back. Amanda and Nick strike up an alliance with Jade: she shows them the secret passage into the vault and they return the real one. They then knock out Trevor and make it look like he was trying to switch pictures.