Tsugu-Min was given the task of awakening "Bill Rizer" from cryogenic stasis. This individual, however, was presumably a clone of the real Bill, as he did not know anything about who he was.
She then proceeded to play him a video message from the Galactic President where he explained the planet was under attack from an alien army known as the Neo-Salamander Force. She then sent him on a mission to stop this threat along with fellow combatant Yagyu Genbei.
After the Neo-Salamander army was defeated, and following her programming, she proceeded to put "Bill" back into cryostasis. After this was taken care of, a fellow Contra soldier by the name of Newt Plissken threatened her. What transpired after that is unknown.
Tsugu-Min's serial number, BR-W9, is a play on "Brownie".
She is apparently an updated model of the CX-1-DA300 Combat Robot, better known as "Browny" from Contra: Hard Corps. Furthermore, both share some similarities such as being tiny robots proficient in the use of heavy weaponry.