According to Digiguide, the third episode of Doctor Who Series 12 is titled Orphan 55. The guide also contained this synopsis:
Having decided that everyone could do with a holiday, the Doctor takes Graham, Yasmin, Ryan to a luxury resort for a spot of rest and relaxation. However, they discover the place where they are having a break is hiding a number of deadly secrets. What are the ferocious monsters that are attacking Tranquillity Spa?
The guide named Ed Hime as the writer of Orphan 55. Hime wrote the Doctor Who Series 11 episode It Takes You Away.
Orphan 55 airs on Sunday, January 12 at 7:10 p.m. on BBC One and 8:00 p.m. on BBC America.