Is this the enemy's new trick?, Kyungsoo ponders, lulling him to sleep?. His eyelids are about to snap shut, though, so it is certainly working.

He's one millisecond away from dreamland when a soft, nasally tune whistles its way into his ears. It's nasally and throaty and everything an opera singer should not sound like, but a few notes in, and Kyungsoo is enraptured (he might even be in love - with the singer's voice, of course). 

Kyungsoo hears that hauntingly beautiful voice inside his head as he sits patiently in the front row of the opera theatre, staring at the curtains masking the deal.