"In the beautiful temple is a seer."
Translation:In templo pulchro est vates.
There is no direct object here. "Templo" is only the object of the preposition "in" and describes where our "vates" is. "Esse/to be" does not take objects because it is a verb of state, not a verb of action.
But yes, you can say "The seer is in the beautiful temple". That is the usual way to say it in English.