If the target player is an illegal target by the time Thought Distortion tries to resolve, the spell won’t resolve and will be put into its owner’s graveyard with no effect. This is true even though it can’t be countered.

A spell or ability that counters spells can still target Thought Distortion. When that spell or ability resolves, Thought Distortion won’t be countered, but any additional effects of that spell or ability will still happen.