Tau Ceti IV was a planet in the Tau Ceti system, twelve years away from Sol. In 2787, a colony named New Cascadia was established on the planet by humanity by the UESC Marathon. The colony repulsed an attack by the Pfhor scoutship Sfiera in 2794 during the events of Marathon (1994), but was destroyed in a following Pfhor attack that year.
The loss of communications between New Cascadia and the Sol system was realized by the UESC by 2795, and in 2797 they sent the UESC Equanimity under Project Goliath to investigate the status of the colony. The Equanimity arrived in 2893.