The Doctor mentions the name of his homeworld, Gallifrey, for the first time in this episode when he and the Sontaran Linx get to talking. Linx has heard of the place.
Oh, and Sontarans are kinda weird.
How are they weird? Well, Sarah Jane had gotten herself captured like all female companions in the Classic Who Era. Linx thinks she’s a different species. Sontarans are all male, and they’re all built to fight wars. There’s something interesting about this sort of character concept. Unlike many of the Doctor’s other enemies, the Sontarans are less evil and more apathetic. All they want to do is fight wars.
That comes up when the Doctor tries to reason with him. Linx is giving Irongron and his warriors rifles, and that could mean nuclear weapons before the Enlightenment. That would be very bad. The Doctor would prefer that not to happen. Linx doesn’t care.
Does Sarah Jane care? Well, once she realizes Irongron, Bloodaxe, and company are not cosplayers (thanks to Linx’s hypnosis ray), she makes a break for it. And she finds the Doctor! And…she runs from him too!
Well, the local Lord had sent a spy named Hal, and Irongron decided the best way to test another one of Linx’s gifts, a radio-controlled robot knight, was to let Hal try to kill something that isn’t even alive. Sarah Jane gets to Hal and the Doctor separately gets to the guy with the remote, removing the threat of the robot. The Doctor stays behind, eventually having the above-mentioned conversation with Linx, and Sarah Jane goes with Hal back to Castle Wessex which is fortunately not having a dull Vikings subplot. And once there, Sarah Jane basically says she believes the Doctor is behind all the kidnapped scientists.
But he obviously isn’t. Let’s be fair to Sarah Jane. She did just meet him. Linx has found the Doctor is immune to the same hypnosis he’s used on most of the kidnapped scientists, all of them forced into repairing Linx’s damaged ship. The Doctor is forced to help with a certain headset, but fortunately, the one scientist the Doctor met back at UNIT hasn’t been hypnotized. He’s too scatterbrained, and he does eventually get the gadget off the Doctor, allowing the Doctor to try and make a run for it.
And then the Doctor runs into Irongron and some others. The Doctor runs around the courtyard, karate chopping people when he can, and then he trips. Irongron doesn’t like people manhandling him, so he brings an ax up above the stricken Doctor. And then the credits role.
Can the Doctor regenerate if he loses his head?