Cho is chosen as Cedric's hostage for the second task. She is bound tightly to the tail of the statue of the merperson in the lake, next to Ron. Cho appears to be in a deep sleep; her head is lolling onto her shoulders, and fine streams of bubbles issue from her mouth. Cho is cut free by Cedric and brought back to the lake shore. She is fussed over by Madam Pomfrey when they return to the shore, and is wrapped in a thick blanket to keep warm.
Cho and the rest of the DA members are taught how to produce a Patronus by Harry in the Room of Requirement. She tells Harry off for being a killjoy when he tells them that producing one there is very different to being able to produce a Patronus when faced by creatures like Dementors. Cho admires her silvery swan-shaped Patronus as it soars around the Room of Requirement in their last lesson of the term. When Dobby arrives to warn Harry that Professor Umbridge is on her way to the Room of Requirement, having found out about the DA group, Cho rushes to the exit with the other students.