She was a rare commodity among Wookiees in that she abandoned her family and two life debts to pursue her smuggling career. Her flouting of Wookiee customs in this way caused Chewbacca to dislike her intensely.
In 17 ABY, she joined Han and Chewbacca in their attempt to rescue Lando Calrissian from the crime lord Nandreeson, along with Zeen Afit, Kid Dxo'ln and Sinewy Ana Blue. Unknown to Han, Wynni's true loyalty lay with Nandreeson and once the rescue party reached the pool in Nandreeson's chamber, Wynni turned on Han and Chewbacca.
At a command from Nandreeson, Wynni joined Afit, Kid, and Nandreeson's guards in attempting to kill Solo, Calrissian and Chewbacca (Blue did not help either side in the ensuing struggle). Wynni and Chewbacca grappled in the pool during the fight, with Chewbacca managing to disarm her and render her unconscious. Afit and Dxo'ln were also knocked out and drowned as a result, but Wynni was more fortunate; she ended up floating on her back and thus able to breathe.
When Nandreeson and his guards had been defeated, Han asked Chewbacca to pull her out of the water and leave her by the edge of the pool, so that she would at least have "a fighting chance" when more of Nandreeson's people arrived. Despite feeling that Wynni wasn't deserving of such consideration, Chewbacca did so.