Hiram is kidnapped by Fidget in the early minutes of the movie to create the clockwork Mouse Queen for Professor Ratigan. Though he starts the project, he is horrified by the whole idea and suddenly refuses to help Ratigan - no matter what - even though he knows he may lose his life. However, when Ratigan threatens to kill his daughter, he is forced to return to the task. It's from these actions that we are shown that Hiram is very caring and loving to Olivia, which may be caused by how the audience is left to presume that his wife is deceased.
Hiram successfully creates the clockwork Mouse Queen in time and is held at gunpoint to operate it. However, he is soon freed by Basil of Baker Street and Dr. David Q. Dawson. He is also reunited with his daughter; sadly, the reunion is short-lived, as Fidget frees himself of his bonds and kidnaps Olivia. With help from Basil and Dawson, Mr. Flaversham assembles a makeshift balloon out of a few actual balloons and the Union Jack.
After the fight at Big Ben, Basil reunites Hiram with Olivia and defeats Ratigan. He is last seen telling Olivia to come along so that they can catch their train.
Flaversham was voiced by Alan Young, who more famously voiced Scrooge McDuck.