Nardole first met the Twelfth Doctor on Christmas Day 5343 on Mendorax Dellora, where a human colony had settled. Mistaking him for a surgeon, the bald, duffel-coat fan took the Time Lord to operate on King Hydroflax - who was married to River Song. It wasn’t long before Nardole’s own head was placed on top of the King’s huge cyborg body.
But, as we discover in New York City some years later, the Doctor kindly reassembled Nardole, placing his head back on his body. The two investigated mysterious goings-on at Harmony Shoal and met human superhero, The Ghost.
The fun-loving companion helped the Gallifreyan after the loss of River Song, ensuring he was never lonely. Nardole also managed to pop off to 12th century Constantinople where he ruled firmly but wisely — he’s also one of the few people to pilot the TARDIS alone!
After looking after Missy in The Vault, down below St. Luke’s University in Bristol, Nardole traveled with the Twelfth Doctor and Bill on numerous adventures. The Doctor left Nardole fighting against an army of Cybermen aboard a Mondasian colony ship.