When Perry comes face to face with an Australian platypus hunter named Liam set out on destroying him, his unwavering demeanor is threatened and his life is put in danger -- he must find a way to defeat this villainous foe, rescue Doofenshmirtz from the error of his ways and save himself from the hunt. Meanwhile, Baljeet is having an existential emergency and finds himself incapable of making decisions, so Phineas and Ferb create an infinite probability generator that will allow Baljeet to make as many choices as he pleases without being affected by the consequences.