The First Doctor #2

'The Longest Story in the World' (2000) from Short Trips and Side Steps.

A very intriguing story about Susan and The Doctor, presumably on Gallifrey, but told with a frame story which allows the specific details to be not wholy accurate in a good way. Here The Doctor doesn't seem to have any understanding of his regenerating capabilities or time-travelling urges, and Susan seems to be somewhat clairvoyant and attempts to convince The Doctor to create a time machine and travel away. She's also an adopted grandchild and her race is different to The Doctor's. All interesting details and actually a gripping alternate-history story of The Doctor, but you believe it because it's well told, so when the frame story comes back it quite smartly makes you kick yourself for getting so into it.