In 2365, Larell and associates Hain, Krit, Nahsk, and Morn, planned and executed the Lissepian Mother's Day Heist, a notorious robbery that occurred on the planet Lissepia, in which one thousand bricks of gold-pressed latinum was stolen from the planet's Central Bank. Though all thieves managed to escape the authorities on Lissepia, Morn double-crossed Larell and the others by keeping the latinum for himself. She let him go for fear of being pursued by authorities.
In 2374, the statute of limitations expired for the crime, so she decided to go after Morn, however, she learned he had died. She soon discovered he left everything to Quark, and so traveled to Deep Space 9. She broke into Morn's quarters and pretended to be his ex-wife, willing to share the latinum with Quark or threaten to pursue a long court battle. Intending to keep the latinum to herself, she stayed close to Quark as he tried to find it, able to discretely steal the account number off of him. Eventually, she found that the other thieves in their group had also approached Quark to get the latinum, and so they all agreed to split it. However, when they all received the latinum in a cargo bay, they pulled phasers on each other and started firing. She was arrested with the others by security. No one realized he had extracted the latinum and stared it in his second-stomach. (DS9: "Who Mourns for Morn?")
Larell is the only one of her species seen on-screen. The name of her species is not named in the episode.
The script for "Who Mourns for Morn?" states the pronunciation of Larell's name as "luh-RELL". It goes on to describe her as a "beautiful Alien woman."