Naoto & Nanako from Persona 4. This is from episode 13 of P4A when Nanako cosplays Lovely and investigates her brother's schedule in summer holiday XD. I can't wait for the new episode of P4A this week! It's Naoto's story!!
my brother and i developed a headcanon sequel based on this where naoto inherits dojima's position and nanako acts as her deputy. theh they go solve supernatural mysteries and it ends up being a game like devil summoner. (i can only dream)