The Doctor and Varan travel down to Solos to search for Jo and Ky but the Marshal orders his men to pursue them.

The Doctor and his friends are led to safety by Professor Sondergaard, who tries to help the Doctor translate the tablets.

The Marshal's premature use of Jaeger's experiment is threatening to destroy Solos' atmosphere and the Doctor returns to Skybase to try and correct the damage.

The Doctor is forced to help the Marshal cover up his actions with the Investigator but Jo and the others attempt to escape to expose him.