Select an enemy follower on the field. Banish it and, if there's a Cute follower on your field, give your leader +3.
QIf there are no selectable enemy followers on the field, and I have a Cute follower on my field, can I still play this spell to give my leader +3 defense?
ANo, you can't. If a spell requires you to select a target, and there are no valid targets on the field, that spell cannot be played at all.