Last episode the big reveal was the people that put the Doctor through the interrogation were the Gallifreyans, his own race. He refused to give them the answer they wanted to, it took 4.5 billion years for him to reach them. The main story was how far he would go to save Clara, from the fate from two episodes ago. The Gallifreyans wanted to know the identity of the Hybrid. The Hybrid was prophesized to be the product of two warrior races and would break the fabric of time.
The episode showed how the leader of the Gallifreyans had lost his support of the people; however the Doctor had all the support due to his actions in the Time War. That did not last long once the Doctor continued to refuse to tell them who or what the hybrid was. The answer of that question was not definitively answered, but the episode did lay out several plausible possibilities.
This episode followed a similar theme to the end of the Tenth Doctor’s partnership with Donna Noble; the results of the actions in Hell Bent are a twist on the fate of Donna Noble. Telling the exact details would be complete Spoilers. It also sets up a possible spin-off. This ends the Doctor’s association with Clara Oswald in an interesting way.
I enjoyed this episode immensely and it gave me what I wanted to see. It took many turns I did not see coming. Overall I give this one an A+.