Describe a simple activity you could have reasonably performed in 1 round in the space within 30 feet of you at some point within the last hour. The activity could be hiding a key under a rock, placing poison in a cup, sticking a disguise in a nearby closet, or something similar. The activity can't directly affect a creature other than you or an object being worn or carried by someone other than you. The result of the activity then becomes real, just as if you had in fact performed it: the key is under the stone, or the cup now contains poison.

When the spell ends, you instantly travel back through time to a point up to an hour before you cast this spell and carry out the activity. When you finish, you disappear and return to your normal place in time, 1 round later. If you are unable to complete the activity when the spell ends, you suffer one level of exhaustion as your personal timeline becomes fragmented. A level of exhaustion suffered in this way can't be removed until you finish a short rest during which you are able to complete the activity, and travel back through time and do so.