What if aliens came down to you and offered you a job, arguing that Earth would never appreciate what you have?
That, strangely enough, happens to inventor Nikola Tesla, but the aliens want him to do very bad things.
That’s where the Doctor gets involved.

SPOILERS BELOW

It’s an interesting tale about how Tesla’s genius doesn’t get appreciated in 1903, compared to Thomas Edison making money thanks to his inventions produced in his facility. There’s also hints about the AC/DC controversy that was featured in The Current War, and suspicions about Tesla because he’s an immigrant and claims he’s gotten signals from Mars.
Thing is, he has, but not from Martians. They’re from her….

She’s the Queen of the Skithra (Anjil Mohindra), and her race of space scorpions take what they want for conquest, mainly tech from other planets. Her next target is Tesla.
As the story begins, though, he (Goran Visnjic) is having a tough time trying to get funding for his Wardenclyffe project that can generate energy and radio waves over the air. Someone is also stealing parts from his hydroelectric plant. He and his assistant Miss Skerritt (Haley MacGee) find someone trying to shoot them.
The Doctor, though, is also there. She’s tracking down a strange signal and thinks Tesla might have something to do with it. He admits he’s found a floating green ball that generates a lot of energy. He could use it for his project. She recognizes it as an orb from an ancient race used to spread knowledge. but the Skithra hacked it to scan the Earth for anything they can use…or anyone.

Meanwhile, Graham, Yaz and Ryan get an idea of what life was like in 1903. They learn about how some people don’t like Tesla, and fear that alternating current (AC) could kill people. They also meet Edison (Robert Glenister), who sees inventing only as a way to make money. He supports direct current, and maybe wants to take over Tesla’s power plant.

The main problem, though, is the Skithra invading while they look for Tesla. It even includes killing some of Edison’s assistants. Eventually, they grab Tesla and Yaz, and force him to work for them. The Doctor rescues them with something called a Braxian Bouncer, but the Skithra is determined to get Tesla or it’ll destroy the Earth. He’s even willing to surrender, but the Doctor thinks she can use the Wardenclyffe tower to blast a ray to destroy the alien ship. They’ll have to work fast because they’re coming to get Tesla.

Edison, of all people, creates a distraction to get people away, just as the aliens arrive. Sadly, the CGI of the aliens isn’t very good. They look like they escaped from a video game.
The Queen decides to get Tesla herself, while showing contempt towards everyone. That’s the one flaw in her. She could be a formidable opponent, but she’s way too arrogant to be taken seriously. Her minions do most of the killing, but shouldn’t be the deadliest of her species? Her role is mainly making threats and showing distain towards Earthlings. It’s bad enough her people have no tech of their own because they steal from everyone else.
The Doctor takes advantage of this to send the Queen back to her ship while Tesla zaps it with his lightning bolt from the tower.

The people pass it off as another experiment of Tesla’s gone wrong and that’s OK with him. He and Edison also get to remember everything, even visiting the TARDIS because no one would believe it.

One more thing: the episode gives an interesting picture of the rivalry between Tesla and Edison, and how one got rich while the other did not. Tesla thinks the idea is important while Edison thinks the best inventions are the ones that make money. Thing is, Edison used the discoveries of his assistants to create the inventions he is credited for. As Tesla says to him, “You’re not a man of vision, you’re a man of parts.”
It’s not too far-fetched to say the Skithra Queen is a “Queen of parts.” She takes from others because her people can’t make something by themselves. It’s not for profit, though, it’s for power. Of course, it backfires on her. That’s why we remember Edison rather than a scorpion queen with no imagination.

Even though Tesla never got rich, his ideas such as hydro-electric power, the Tesla radio coil and AC affected generations. He’s also had an impact in rock music and electric cars. As he tells the Doctor, “The present is theirs. I work for the future, and the future is mine.” It’s a nice ending, and a sign the season’s back on track,
Next week, an old enemy is back, and is targeting Gloucester for some reason.