YSS Plumeria, NG-X1-390, was a Plumeria-class Medium Gunship built at Gemini Star Fortress by Ketsurui Fleet Yards in YE 29 for the Star Army of Yamatai's First Expeditionary Fleet. It was captained by Taisa Ketsurui Hanako after the destruction of her previous starship, the YSS Sakura. It was destroyed by Mishhuvurthyar less than a month after its construction, and was replaced by the YSS Elfin Princess.
After the Second Battle of Urghflau, the Star Army of Yamatai's First Expeditionary Fleet was left in shambles. To replace lost ships, new ships were immediately ordered from Ketsurui Fleet Yards via the Nataria Fleet Depot. The Plumeria was one of these ships, built at Gemini Star Fortress. After installation of some new systems, the Plumeria stocked up at Nataria System and set off for her first mission, a daring and risky attack on SMX headquarters at Hukka. After a frightening escape, they returned home to take it easy for a while. That didn't last long.
Just days later, the SMX, enraged by the Plumeria's attack, consolidated several battle groups into a large four-wave force (which included a Shlarvasseroth-class Flagship) and attacked Tatiana and Nataria System. The Plumeria took moderate damage but was able to last to the end of the fight. Seeking Melisson (who had suggested ways to defeat the SMX flagship during the battle), Hanako contacted YC-28 and set course for Nepleslia, Elysia, and later a nebula 40 light years to the north, where the ship and Irim-class YS-60 were destroyed in combat by Melisson.