A stroke of lightning forming a 100-foot-long, 5-foot-wide line blasts out from you in a direction you choose. A creature in that line makes a Dexterity saving throw, taking 5d10 Lightning damage on a failed save or half as much damage on a successful one. Each time a creature has been affected, the lightning immediately changes direction toward the closest creature within the line's remaining distance that hasn't been affected by it this turn. The lightning ignores half and three-quarters cover and can travel around corners, but can't pass through solid objects.

Using a Higher-Level Spell Slot. The maximum length of the line increases by 30 feet for each spell slot level above 4.