the Garden of sinners / recalled out summer

A gag manga featuring numerous characters from various Type-Moon works in a school setting.

Lord El-Melloi II and Gray visit Singapore in the summer for a lecture at its Clock Tower branch. In this country where diverse cultures blend, the two encounter a young man named Ergo. Pursuing this enigmatic youth, the Six Sources of Atlas appear.
What is the ancient experiment conducted by the Atlas Institute, the Wandering Sea Baldanders, and another magician? And what is the name of the God that El-Melloi II will come to question? 

The Adventures of Lord El-Melloi II, where magic and legend, fantasy and myth intertwine, now begins.