The Power of the Doctor

S13 E9: An eccentric yet compassionate extraterrestrial Time Lord zips through time and space to solve problems and battle injustice across the universe, traveling via the TARDIS (Time and Relative Dimensions in Space), which is his old and occasionally unreliable spaceship that resembles a blue police phone box (but changes its appearance depending on its surroundings) and is much, much larger inside than outside.