After narrowly missing the Massacre of St Bartholomew's Eve, the Doctor and Steven took on board a young girl named Dodo Chaplet. Dodo brought a cold virus to the far future, which nearly annihilated the humans and Monoids travelling on "The Ark". It was cured and when the TARDIS arrived on the Ark 700 years later the TARDIS crew helped the humans reach their destination, the Monoids having taken over the Ark. One of the First Doctor's most deadly foes was the Celestial Toymaker, who forced him and his companions to play deadly games and briefly made the Doctor invisible and mute. Eventually, the Doctor managed to win the Trilogic Game allowing them all to escape the Toymaker's domain.