Jo and the Doctor continue to have amazing chemistry. They go on a little trip to visit the Master in prison. The three of them talk for a little bit, everyone is very polite. And Jo Grant, who has been mind controlled and almost killed by the Master several times, smiles at him and waves goodbye when they leave, completely unironically. This girl has my entire heart. Someone please get her a sandwich, the Doctor ate all of hers :(

The whole plot is pretty good, the Sea Devils look amazing, all the side characters/villains are great, specially Capt. Hart and Blythe, the clever secretary. The pacing is also great, which is a must for a 6-parter. You can really tell the BBC was giddy with how much stuff the Navy was letting them use for this story: so many guns and boats of all types. The Master and the Doctor on little jet skiis. Jo Grant driving a motorcycle and that huge floater boat thing. 10/10.

The fencing fight is incredibly silly and instantly iconic. Jon Pertwee is chewing that sandwich as fast as he possible can to be on time for the cue for his next line. Amazing.