UMP9 is a member of Squad 404, which has much plot relevance.
Helian contracts Squad 404 to assist with the search for AR-15 in S06. Their first objective is to locate and retrieve the jammer, so they target Hunter, the ringleader stationed to protect the object of interest. However, they all initially underestimate Hunter’s abilities due to the ringleader’s “Elite” modification and thus are forced to retreat. Squad 404 emerges victorious against the ringleader after having engaged in guerilla warfare, yet they are unable to gain information from her because Ouroburos shuts down Hunter’s neural cloud. UMP9 moves to the other side of the sector along with HK416 and G11.
After the unsuccessful endeavor involving Hunter, the group heads towards a safe zone within S06 and reconvenes with UMP45, who brings along a friend. They receive the coordinates of the jammer from SPP-1, a scout from Griffin who has been separated from her escort. Then, they all make their way to the zone with the jammer, but are stopped by Executioner—who happens to be guarding the jammer, and has also received an “Elite” modification . They deal with Executioner in the same fashion as they did with Hunter. However, Executioner has set up explosives throughout the area as a last ditch measure to take out Squad 404. No harm comes their way because UMP45 successfully negotiates with the ringleader to let them escape the blast radius in exchange for returning Hunter.
UMP9 uses one of her dummies and her phenomenal acting skills to stall Ouroboros in S06 while the rest of the squad retreats. Ouroboros is intent on hunting down Squad 404, so UMP45 concocts a plan to defeat her. UMP9 is ordered to continue using her dummies to mislead any enemies in pursuit.
Eventually, Griffin and Squad 404 emerge victorious. UMP9 waits outside the command post for UMP45 to return from finishing the job.
Taking up another contract, Squad 404 is sent to aid the AR squadron in the event of Arctic Warfare.
A later contract has Squad 404 to infiltrate Sangvis Ferri controlled territory and recover an UAV, but the mission turns out to be less straightforward than it sounds.
404's latest contract, at the request of Angelia, they are to assist the newly formed Defiance squadron in their operations against SOCOM units.