That episode was only saved from being as bad as the first because of Cumberbatch and Freeman, who were both magnificent, and the ending.
The story was absolute garbage and it had pretty much started and finished within the first 5 minutes.
Don't expect much from the final episode but the quality of the writing has absolutely plummeted since season 2 so I won't be sad to see it go. Moffat strikes again.
Acting saved it from being a catastrophe but the story was comically bad again.
Not as coherent or good as episode two.
Wasted use of the characters, thought they were copying a saw film for several scenes.