Lethe (The Parliament of Rats)

Lethe was an ocean planet named after the mythical River Lethe. Humans lived on the world's islands. (PROSE: The Parliament of Rats) During the War in Heaven, it was a time-front world and the site of the Lethean Campaign. (PROSE: The Book of the War)

History
Early in the War in Heaven, the last crusade of the Second Wave took place on Lethe. The battle lasted for over a year and was the only official use of casts and babels during the War. At one point, a firestorm raged across the surface of the planet for years. (PROSE: The Book of the War) After the Time Lords ultimately left the planet, it remained ravaged by time fractures.

When humans lived on the islands of Lethe, the time field was full of striations, meaning that time-sensitives were required to navigate the waters. A section of the planet was ruled by the Autarchy, who worshipped the god Om.

A validium staff left by the Time Lords on the planet eventually pulled in the Doctor's TARDIS, and the Fifth Doctor and Nyssa were rescued by the crew of the Lung of Heaven. After an encounter with the Parliament of Rats and its White God, the Doctor commanded the staff to dissolve. (PROSE: The Parliament of Rats)

Lethe (The Parliament of Rats)