"You bound me with a contract only your death could end—and you thought me the fool?"
—Liliana Vess

Settle the Score

Exile target creature. Put two loyalty counters on a planeswalker you control.

Jumpstart

Dominaria

Both loyalty counters must be put onto the same planeswalker.

If the target creature is an illegal target by the time Settle the Score tries to resolve, the spell doesn’t resolve. You won’t put loyalty counters on a planeswalker.

You don’t choose which planeswalker receives loyalty counters until Settle the Score resolves. If you don’t control a planeswalker, you’ll simply exile the target creature and not put loyalty counters on anything.