Der letzte Kampf (1923)

The industrialist's daughter has been kidnapped by the mad inventor Ravello, but Harry Peel stays hot on their trail with the help of his dog Greif. Behind a waterfall, he discovers the hidden gate to Ravello's castle, where the fiercest of battles now break out between the two and Harry finds himself confronted with a staircase that has been electrified and, once again, with the deadly robot.