Although at times it's quite eerily claustrophobic, this isn't the best story for the Time Lord. It actually starts as if bits of it are missing. We find the four already trapped in the TARDIS with everyone behaving erratically. It's almost like they've never met - there's certainly not much trust to be seen. Their time machine won't work and the "Doctor" (William Hartnell) has been hit on the head. "Barbara" (Jacqueline Hill), "Susan" (Carole Ann Ford) and "Ian" (William Chesteron) must try to stop squabbling, violently at times, long enough to piece together the mystery. Could it actually be that it's the TARDIS itself that is causing the problem? If so - is that a good thing or a bad one? The entire series is filmed within the confines of a small set and that shows the limitations of the camerawork. At times it provides for intense close ups that can be quite effective, but for most of the rest of the time it tries to squeeze too many people into the shot and there are repositioning camera/cast shadows all over the place. It's got a little tension, but not enough jeopardy.