Cabal Therapy

To determine the total cost of a spell, start with the mana cost or alternative cost (such as a flashback cost) you’re paying, add any cost increases, then apply any cost reductions. The mana value of the spell is determined only by its mana cost, no matter what the total cost to cast the spell was.

A spell cast using flashback will always be exiled afterward, whether it resolves, is countered, or leaves the stack in some other way.

You name the card as Cabal Therapy resolves, not as you cast it. Then the targeted player reveals their hand and discards if appropriate. No player may choose to take actions between you naming the card and the targeted player revealing and discarding.