Remembering the past when the three of them are together. Playing together, cooking together, and got scolded together. It was a nice memory. But those are just memory of the past.
Drake remembers the promise that remembers that the promise that his childhood friend gave to him and Stella 

" when both of you turn adult I will send a message to the orphanage about me and invite you two to my place, until then take care of Stella for me, OK big guy? And Stella stop being a cry baby when we meet up OK!"

5 years have passed since that promise. And a letter came to the orphanage.

This is a story about a group consist of people of difference race and background, they travel around the world in order to find their friends, and uncovering the History about the word of Vovea.