The Melancholy of Haruhi Suzumiya, Vol. 10 - manga

Quite out of the blue, Kyon receives a phone call from his middle school classmate Nakagawa. Six months ago, he spotted Kyon walking with the most beautiful girl he'd ever seen and instantly fell in love! Now he wants Kyon's help conveying his feelings. But Nakagawa has no idea that the fair maiden who stole his heart is actually an otherworldly being...Nagato?! How will the stoic alien react to Nakagawa's affections?!