The Legacy of the Lost Key - 1 - Grain of Sand

WELCOME TO THE WORLD OF MYSTERY AND MAGIC

So, this is about two siblings who lost their parents to... buying milk. I know it's weird, but it seems like that's the case. And that was several years ago. 1996, to be precise.

Coming back to the story's plot, 2003, we have Adam and Emma, the two siblings, spending their vacation. Then, Emma discovers something unusual. Now... they want to find the origin of Mr. Something Unusual. So, they embark on a quest for the same. And the goal? They have no idea. Neither do I.