The Arc of Yesod

The Arc of Yesod is a video game by Odin Computer Graphics published in 1985 for the Sinclair Spectrum and Commodore 64. It is the sequel to Nodes of Yesod.

The Monolith, object of the previous game, teleported off into space just as Charlemagne 'Charlie' Fotheringham-Grunes was completing his quest. He has followed it to its home planet of Ariat and must now finally destroy it, before the Ariatians download the data it has collected and employ it to destroy the Earth.

The game is very similar to Nodes of Yesod. Charlie must penetrate the alien city where the Monolith is being held, via a network of underground caves and tunnels, and make his way to the Security Centre, where the Monolith can be disarmed and destroyed.