"Firenze saved me, but he shouldn't have done so.... Bane was furious... he was talking about interfering with what the planets say is going to happen.... They must show that Voldemort's coming back .... Bane thinks Firenze should have let Voldemort kill me.... I suppose that's written in the stars as well."
The sentence in bold looks ungrammatical to me. I think that sentence can be separated into two sentences:
he was talking about interfering with what the planets say.
what the planets say is going to happen.
The original one simply puts those two sentences together, which doesn't look grammatical.
Maybe, I just misunderstood it. What's the correct way to understand it?
-- Excerpted from Harry Potter.