Yousef Bey (John Carradine) is summoned to the Egyptian temple of high priest Andoheb (George Zucco) and given a new mission. Since the previous excursion of one of the priest's minions to America which included the depositing of the revived mummy Kharis (Lon Chaney Jr) in the small town of Mapleton, didn't entirely succeed, it's time for another try. In this instance, Yousef is sent to track down the reincarnation of the Princess Ananka, Kharis' true love from centuries past, but even before he arrives there the undead has been brought back by the unwise meddling of a local professor (Frank Reicher) who quickly learns the error of his ways at the hands of Kharis...
For the third in the Kharis series (the Boris Karloff original wasn't really part of it), Lon Chaney Jr was brought back, but not from the dead, to essay the shambling role he had made his own in the previous instalment. He had made it his own because presumably nobody else wanted it as here he was yet again covered in Jack Pierce's makeup meaning the extent of his necessary acting was minimal at best. Carradine was a welcome addition to the cast, but didn't have much of a chance to perform alongside the rest of them, meaning the greater running time was given over to the unappetising romance.
That romance was between two Mapleton college students: the irritating Tom (Robert Lowery) and the beautiful Amina (Ramsay Ames) who is our reincarnation of the Egyptian princess, although it's made clear that she is still an all-American girl. Once Kharis is on the rampage again thanks to the meddling of the professor (who pays dearly) Amina becomes jittery, although she never seems to realise that it's down to her past life. Incidentally, we saw Kharis definitively killed off in the previous film, but here he's shuffling around as good as new, so where has he been all this time? Weren't his remains shovelled up and thrown away last time?
If they weren't perhaps they should have been, as the mummy, no matter where he goes during the day, certainly rules the night. He tries to strangle everyone in his path and does pretty well at it, making at least two tearful widows along the way. Once Yousef appears, the dastardly duo wind up at the museum where the coffin containing Ananka is supposed to be held, but after opening it the body is unable to be revived because... it's not there. After smashing up the place and bumping off the world's oldest security guard, Kharis and his assistant realise the reincarnation is what they should be looking out for and she's getting very distinctive as her hair gradually turns white. Boasting a surprisingly downbeat ending, The Mummy's Ghost was average of its kind, but at least a slight improvement on The Mummy's Tomb.