Gosick ep18 05m 37s

A generic memento box.

The Memento Box is a small box whose contents include a particular person's belongings, deliberately stored in the box as a reminder of that person's life. A particular memento box, which belonged to an inhabitant of Saillune, became a target of two opposing sides — the Science Academy and the Ministry of the Occult. In a race to obtain this object, two spies from each side blended in with the evacuees of the flooded down Beelzebub's Skull in an attempt to locate and secure this item.