There must have been something about the TARDIS because she felt warmer even before she stepped inside it. Inside it didn't even look like she remembered, but she couldn't think of anything else to explain it.

The creature seemed happy to drift inside and Jo let it go. But she looked at it, still looking like Cliff, as she nodded at the Doctor's definition of Christmas.

"I should go," she said. "Cliff will be waiting for me." But she stayed just inside the doorway. "You do have someone to spend Christmas with, don't you?"