Lin's friend, Airi, is being stalked. The three brothers immediately come to her aid, saying they'll take care of the stalker. They sneakily follow Airi around and soon find out it's not just a stalker that follows Airi around...
I leave the rest to you. 
I'm going to bed.
Te dejo el resto. Voy a dormir.
Te dejo el resto. Voy a dormir.
O resto é por sua conta. Vou dormir.