Clear the Mind

House Dimir Spell
Level 6?
Casting Time: 5 Minutes
Range: Touch
Duration: Until its triggering event is fulfilled or until dispelled by some other influence.
The caster and target must be willing. As this spell is cast, the caster chooses a memory that they have. This memory must be of a single person, a single event (even if it involved multiple people), a single group of people that all share the same group name, a single place (even a place as large as a continent with smaller places within it), or a single object / group of objects that belong to a single larger object. The caster forgets this memory for the spells duration. While they are choosing the memory for the effect, they also choose the event that will cause this spell to stop. This event must involve people places groups things and/or objects that are known to them and must be plausibly able to exist sometime this year.
(This spell does have holes. If the caster chooses to forget a group of people and someone renounces or otherwise removes themself from that group, they will remember that person. Loopholes such as this are viable and edge cases must be cleared with the DM at the time of casting to make sure both parties have a clear understanding of this spell's ramifications.)