2 years ago, Taeyang's car collided with a truck and he could not remember if what he remembered is his reality or things that existed only in his head. His doctors cleared him for active duty back in the agency but the team's leader, Kwon Jiyong, still wasn't so sure.

"Are you sure you're ok Bae?" Jiyong asked the same question for 1 whole month and Taeyang was sick of it. They had a small quarrel but the two had a long history with each other, they didn't see the need to continue ignoring each other.

"Taeyang hyung, someone left this letter on your table." Seungri walked over to Taeyang's table and was excited to see who it was from. Before Taeyang could scare the maknae away from his table, Daesung came and stood excitedly next to Seungri.

"Ya, the two of you have nothing to do?" Daesung and Seungri looked at each other and back at Taeyang, shaking their heads.

"Hyung, looks like a letter from a female! Who could it be who could it be who could it be?" Daesung smiled widely and his shoulders went up and down excitedly.

Taeyang looked at the two of them again and the younger ones started to pout and walked back to their own tables. Taeyang finally had his own space and he grabbed his letter opener.

"Kang Ji Woo, or should I say, Dong Youngbae. I hope you're recovering well." Taeyang looked around and wondered who could've sent the letter. Taeyang have been part of so many undercover missions, he couldn't remember all the names he had took. Taeyang knew that some of the missions were classified, which means he couldn't just go around asking his team questions, he needed to solve this by himself.

But how? Will he be risking his own life or his team mates that he have regarded as his family?