Yajilin+. Follow regular Yajilin rules (draw a loop on cells’ centers and shade the unvisited non-given squares black so no two black squares share an edge; clues show the number of black cells in the given direction). But the directions of the arrows are unknown; it’s one of the given two directions. (The other direction may or may not have the given number of black squares.)
Sometimes there seems like not enough clues to solve a mystery, but it solves cleanly anyway. Sky has tried to construct such mystery, and apparently he’s satisfied with this easy-medium brainteaser… Need to put even less clues.
Puzzle 45: Which Way
Yajilin+
It might be very early to tell this, but stay tuned for May 2013.
Chaos at the Sky 