David Tennant is my favorite Doctor. His Doctor is generally a cheerful, god-like hero. It’s no surprise then, that my favorite episodes of the show Doctor Who are ones from the seasons starring Tennant. “Midnight” from season four is one I like to watch again and again. This episode lands in the timeframe when Donna is the Doctor’s companion. Donna may have never been a love interest for the Doctor, but she understands him in a key way that his other companions do not: Without his companions, he’s scary–at least this Doctor is. While the Doctor may keep companions around to fend off loneliness, the real reason may be that they keep him grounded in reality, something necessary for a true hero to remain so.

As far as episodes go, “Midnight” could be written of as a filler episode, having not much to do with the long-term plot of the series. If one had to cut an episode due to time constrains, “Midnight” would be a good choice as it wouldn’t affect the series as a whole and is rather forgettable coming after the epic episodes of “Silence in the Library” and “Forest of the Dead.” However, taking a closer look, “Midnight” has quality in its own right and deserves to be showcased as more than just filler.

The episode starts with Donna and the Doctor on vacation on a planet called Midnight. Donna’s busy sunbathing, so the Doctor decides to take a tour out to look at the planet which appears to be incapable of supporting life. In itself, the plot would make a great horror movie, but at the same time apart from the Doctor Who universe “Midnight” has little meaning and in fact is only truly scary because of who the Doctor is.

Tennant’s Doctor is always rather curious and chatty, so he wastes no time in getting to know the other people on his tour ship. They are all humans and although this may be the future, they are not depicted as being much different from those in Doctor Who’s present day London. Three are on a family trip, one just broke up with a lover, two are scholars, etc. When the ship unexpectedly stops due to a malfunction, Doctor Who is eager to help and invades the cockpit to talk with the pilots and maintenance men. In what will prove to be a foolish move, the Doctor encourages the men in the cockpit to lift up the sunscreens so he can take a look at the planet. Although they think him merely curious, the Doctor’s real goal is likely to spot a way out of their dilemma. Still, he’s thrilled they are looking on an area of the planet that no one has ever seen before. It is towers and mountains encrusted in diamonds and all uninhabitable due to the proximity of the sun. One of the pilots spots a shadow sliding towards their ship, causing a prompt closing of the viewing screens.

Back in the main cabin, the Doctor finds himself having to settle down the increasingly hysterical passengers who are all afraid they will run out of air before help gets to them. Both the flight attendant and the female scholar are key in helping him calm everyone down. This foreshadows how the two women will ultimately play a role in saving everyone at the end. Why these women are able to see what the rest of the group does not, the writers give no answers, only that perhaps one is thoughtful in a unique way and that the other has genuine concern and care for her passengers. These are both qualities that are easily found in each of the Doctor’s companions.

Just as the passengers are relaxing something knocks on the walls of the ship, presumably trying to get in. Hysteria rises again, ending with the cockpit getting ripped away from the ship and the lights turned out. As everyone comes back to their senses and gets the lights back on, they realize that one of the passengers, a Sky Silvestry (Lesley Sharp), who was extremely afraid, has been so traumatized that she cannot speak. It doesn’t take too long for the Doctor and passengers to figure out that whatever being was outside is now somehow in this woman. Applause to the actress who created a chilling character within such a short amount of time. Her performance as she mimics and manipulates the other passengers is riveting. Not only does she shine but allows Tennant’s Doctor to shine as well, not to mention the other passengers. This is the sort of scene that really tests actors–closed room, no specials effects–as well as the writing, both of which are very good in “Midnight.” It is a scene that I can imagine would be of good use in an acting class or workshop.

With this discovery of an entirely unknown and new creature in the universe, here the Doctor’s penchants for both curiosity and hubris conspire to within a hair’s breadth of his complete downfall. We see him at first having control of the situation and then quite suddenly stuck, unable to do anything to change or affect events around him. His life is at stake with no way out. We know that if Donna was with him, this would not have happened. If Donna was with him, she would have held him back, and in the end it is the two stand-in companions, the flight attendant and the young scholar who save the day, one by contradicting the lie that is gaining power in the room, and the other literally giving her life to save the passengers and perhaps the entire universe. The Doctor is extremely shaken by this whole experience and this may be the part where he becomes too cynical to recover. Though he shares what happened with Donna, I didn’t come away with the impression that she really understood just how dire circumstances were or what an amazing sacrifice the flight attendant made. The attendant didn’t just save one life or a group of lives, she saved all of the lives in the Doctor Who universe.

A space tale about an undiscovered malevolent being could be an exciting movie, but this episode has such tension because it’s about Doctor Who. The new creature is frightening precisely because of who the Doctor is. The Who universe would not be able to thrive, much less exist, without its main character. “Midnight” foreshadows this particular Doctor’s end, should he continue to be companionless, and it is this factor combined with his reckless curiosity and growing self-pride that ultimately leads to his regeneration into someone new, kinder, and smarter.

Of all the Doctor Who episodes from Tennant’s run on the show, “Midnight” truly seems to encapsulate his character. It’s an episode that can be watched again and again, not only for the fine acting and writing, but for the lessons on group dynamics and the false appeal to compassion. Can there be any worse phenomenon in the universe than someone advocating for a clear, present danger to be welcomed unquestioningly into a benign group? Some evils are not to be understood nor negotiated with, but only to be defeated. It is no wonder that the Doctor found his life rightly questioned in the next instant. True love, true compassion, is giving one’s life for one’s friends, in this instance the flight attendant sacrificing herself for her passengers. She saved the Doctor, but shamed him beyond all repair, and although he is unarguably at his worst in “Midnight” it is by far my favorite episode.