The following contains spoilers for tonight's episode

On tonight’s penultimate episode of this season of Doctor Who, “The Legend of Ruby Sunday,” the Doctor (Ncuti Gatwa) and Ruby (Millie Gibson) head to UNIT to try to find the truth of her past, as well as the identity of the mystery woman, Susan Triad (Susan Twist), who has appeared in every episode of the season. Opening a time window at UNIT, they recreate the Christmas Eve when the Doctor found Ruby from an old surveillance video, but there is something there that shouldn’t be. Can they figure out what truly happened and how it connects to Triad Technology before it’s too late?

This definitely once again felt like a classic, though more serious, episode of the series. Both Gatwa and Ncuti shined. I also appreciated that the Doctor once again jumped headfirst into danger, knowing that it was likely a trap, although it was also refreshing to see him learn that there can be consequences for that as well.

As with every episode, the visuals were grand, and the idea of the tech of the time window and recreating a moment in three dimensions was really cool and really pulled you into that moment.

Bringing back in familar characters like Kate (Jemma Redgrave), Mel (Bonnie Langford), and Rose (Yasmin Finney) of course was very welcome and helped amp up the episode. It truly had me riveted from the first moment to the last. Russell T. Davies’ storytelling worked to finally bring everything full circle as the Doctor starts to connect the dots. I was definitely happy that the Susan twist (see what I did there?) wasn’t a red herring or a tongue-in-cheek joke and did actually have meaning, but I liked that the surprise was kept until the very end. There had been much speculation across the internet in the past few weeks that “S. Triad” was an anagram of TARDIS, which proved to be true, but it was clear that the crumb was only left to throw fans off, but I did love how that as well as the Susan being his granddaughter theory played out until the very last moments of the episode. There have been so many clues dropped through the whole season and the anniversary specials for people who payed attention and they didn’t drop the ball with any of the story threads. Something big was definitely building and there was suspense in spades. I couldn’t turn away. It seemed to be obvious that whoever the big bad, or “the one who waits” was would be someone from the Doctor’s past. I can’t claim to know enough about Classic Whoto actually know who Sutekh is, but the reveal was still spectacular. The only question we are really still left with now is who Ruby’s mother is, but it would make sense for that to sit on the back burner for the moment.

Overall, “The Legend of Ruby Sunday” was a stellar episode, and I’m excited to see where it goes next week with the conclusion. The only negative? No more episodes for a long while. Still, I’m sure it will be worth the wait. It always is.