The Spiders

The Spiders (German: Die Spinnen) is a German silent serial adventure film written and directed by Fritz Lang. It was released in two parts in 1919 and 1920. Two more parts were originally planned but never made. It was believed to be a lost film, but has been rediscovered and restored.

Part 1. Der goldene See ("The Golden Lake"):

In San Francisco, well-known sportsman, adventurer and traveller Kay Hoog announces to his club that he has found a message in a bottle with a map drawn by a Harvard professor who has gone missing. The message tells of a lost Incan civilization that possesses an immense treasure. Hoog starts an expedition to find the treasure, while the crime syndicate "Die Spinnen" sends out a rival expedition led by the beautiful but dangerous Lio Sha. 

At the Golden Lake, Hoog saves the Inca priestess Naela and falls in love with her. He takes her home with him after discovering a mysterious clue about a diamond ship. Back in San Francisco, Lio Sha declares her love for Hoog but he rejects her in favour of Naela. Lio Sha has Naela murdered and Kay Hoog swears revenge.

Part 2. Das Brillantenschiff ("The Diamond Ship"):

The search is on for a Buddha-head shaped diamond that has special powers. Carried in the hands of 'a princess' it will bestow the power to rule Asia. In San Francisco, Hoog discovers a hidden city underneath Chinatown but he is found out and taken prisoner. Eventually the hunt brings Kay Hoog to England, where the Spiders kidnap Ellen, daughter of diamond king Terry whom they suspect of owning the stone. When Kay Hoog arrives on the scene, he and Terry discover (with the help of an ancient log book) that Terry's pirate ancestor concealed a map in a painting. 

Hoog follows the map to the Falkland Islands to find the diamond, but Fourfinger-John, who has spied on Terry and Hoog, manages to inform the Spiders by carrier pigeon. Lio Sha and her henchmen catch up with Hoog in the cave where the pirate treasure is hidden and take him prisoner. However, poisonous fumes from a volcano enter the cave and all the criminals die. Only Kay Hoog manages to escape with the stone. Back in England, he works with the police and Terry to free Ellen from the clutches of the Spiders' hypnotist master.