Plot hole: The Polar Bear King (human version) is held hostage at the witch's castle. When the witch comes to pay him a visit in his cell she unlocks the door very elaborately. It is very surprising that the witch is not surprised at all that a) one of her subjects is inside the cell advising her captive on an escape plot and b) that this subject made it through the locked door.
Plot hole: On arrival at the Summerland castle the Polar Bear King becomes human during the midnight hour (as part of the spell) and performs his husbandly duties with his carry-on wife. Why did he not become human during the journey from Winterland to Summerland which took several days?