The good non-Doctor Who story

For being the final pure historical, they tried something different, by having this Agatha Christie like murder mystery. The first episode is really fun, as the characters are just hanging out, but the second episode is a bit dull with the ending cheating by having the reveal being predictable for the audience, but impossible for the characters to figure out, but somehow the Doctor figured it out. The Nyssa and Ann stuff is cute, and Tegan probably had the time of her life, and Adric ate. The big issue is that if you get rid of the TARDIS team, not much changes, and it doesn't feel that much like Doctor Who. Also George Cranleigh is a victim and his mother and Charles should be in prison.