The story takes place aboard a battleship staffed by anthropomorphic cats (which strangely look more like dogs with their small ears), most of whom are singing "The Song of the Marines (Shovin' Right Off Again)" as a chorale group.
On the battleship, anthropomorphic cats, which have ears resembling those of dogs, often perform "The Marines' Hymn (Shovin' Right Off Again)" in unison, creating a choir group.