You cloak yourself in a protective field that absorbs incoming magic, rejuvenating your spell slots.  When you are the target of a spell (including spells that affect multiple targets, but not area spells such as fireball), make an ability check using your spellcasting ability.  The DC equals 10 + the spell’s level.  On a successful check, the spell has no effect on you and is absorbed by the field.  You regain a spell slot of the same level as the spell that was cast against you.  If you have no expended spell slots of that level, you don’t regain a spell slot, but this spell remains in effect.  Even if the spell manages to bypass the field, you gain advantage on your saving throw.