Mimosa II was the second planet of the Mimosa system.
In 733, the Fourth Doctor and Leela (PROSE: Lords of the Storm) interceded with the Tzun Confederacy's colonization of Mimosa II, being responsible for the loss of the Stormblade Ksorn, Councillor R'Kyth, and the complete expeditionary force, leading to the Tzun abandoning operations there.
Twelve hundred and twenty-four years later, all strategies employed by all parties involved at Mimosa II were analysed and incorporated into the Tzun central tactical database. Because RNA grafts were updated with each generation, First Councillor Shok'Arl even remembered the Doctor telling Councillor H'Kauth "What goes around comes around." (PROSE: First Frontier)