Knox acquired his Type 70 TARDIS from a Nekkistani dealer on Gryben. Knox first met the Sixth Doctor when he was contracted to give humans an alien flu virus to help cure an alien race. During this time Knox also placed a few days in 1828 in a time bubble so he could charge alien businessmen to watch the suffering of the humans in that period. Knox was stopped by the Doctor, who destroyed the time bubble and purposefully infected Knox with the alien virus. (AUDIO: Medicinal Purposes)