Swamped

Well. For a moment, forget the fact that this is time magic. If your guess is correct, you're dealing with a spell you don't want to get rid of entirely - otherwise he might not be able to return - but that's having an unwanted effect.

So in effect, you want to put a lock on it. Hide it away and pull it out later. You've had some practice with that; back at the library, you sometimes had to move spells from one book to another, in order to keep the spell active as the book itself decayed. Of course, in most cases the wizard who originally cast the spell wasn't alive any more, so you didn't encounter resistance in the other direction, and you aren't certain that will be the case here; and you were working from an object to an object, rather than a person to an object. And you also need to keep the spell from just taking whatever object you move it to away.

Well, one issue at a time. The easiest way to keep the spell from taking the object is to use an object that magic doesn't flow through well. It'll make the transfer a little harder, but right now you don't have much time to consider your options.

Fortunately, your room is just next door. You run in and fetch the moonwood stick from your closet. Of course, you keep it wrapped in a cloth so it doesn't affect you too much.

You then run back and start transferring the spell. It's difficult. You end up having to put a bit of it in the cloth, then move it from the cloth to the stick. Hard enough moving a spell from a person to an inanimate object without having to deal with the added resistance of moonwood. Inanimate-to-inanimate is considerably easier, but still draining in this case.

Indeed, after a minute or so, you've got a rather delicate setup. You've worked out the principles, at least, so you can move relatively quickly from here. But if something starts going wrong, it could ruin the whole thing.

And just as you start to speed up, you notice something going wrong. You're encountering resistance. Someone is fighting back.

So what are you going to do about it?