The Sarah Jane Adventures followed up its epic Doctor Who crossover with a surprisingly good story — especially the first half, in which everybody on Earth vanishes, except for three kids. It was the stuff of classic Who. Spoilers ahead.

"The Empty Planet" had a pretty epic first half — Clyde and Rani both bond with their mom and dad respectively, while Sarah Jane notices a weird alien energy signature that she can't trace. And then in the morning, it turns out that everyone on Earth has vanished except for Clyde and Rani... and eventually they find one other kid who's around. The spooky scenes of Clyde and Rani wandering an abandoned London were some of the best moments this show's ever had, because they were atmospheric and kept the mystery ticking over, while giving us lots of nice character moments.

Gareth Roberts, who's always been one of my favorite Who writers (except for occasional lapses like the Agatha Christie thing) really brings it here, with new pieces of the mystery dropping into place every few minutes, like the weird symbols on all the screens, the child who doesn't seem to have any reason to have been left behind, and the scary heraldic noises off in the distance. And then the stompy yellow-and-red robots!

And it's official — Clyde and Rani not only make a brilliant team, they also have incredible chemistry and the little hints that they might wind up dating are almost too tantalizing to bear. This time, Clyde kisses Rani — on the cheek, but still. And they hold hands a bit and talk about how they have each other. I hope we're not being set up for some kind of tragic twist or something. I also loved that both Clyde and Rani are actually quite smart and competent when the chips are down, noticing stuff and working things out — including the reason why the two of them weren't taken when everyone else was.

With a story like this which has a really spooky, clever first half, the big question is always going to be — is the second half going to be a horrendous letdown? Are we going to find out it was a dream, or a test, or some kind of time-travel thing, and there's going to be a magic solution? But no — there turns out to be a super-logical explanation for everything that happens, including why everyone was taken (they were hostages) and why Clyde and Rani weren't (they've been grounded by the Judoon.) Plus a countdown and a thrilling last-minute save. You can't really ask for any more than that. Oh, except maybe for becoming nobility on an alien planet and getting pizza.

What did you think?