On the planet Vortis, the Doctor and his companions aid the butterfly-like Menoptra in their battle against the parasitic Animus and its mind-controlled minions, the ant-like Zarbi.
as The Doctor
as Barbara Wright
as Ian Chesterton
as Vicki
as Animus (voice)
as Vrestin
as Hrostar
as Hrhoonda
as Hlynia
as Hlynia
as Hillo
as Hetra
as Nemini
as Zarbi
as Zarbi
as Zarbi
as Zarbi
as Zarbi
as Zarbi
