How about this time you search for the [plur]Seiren Treasure Chest[pl:"Chests"]?

This mission isn't hard, but you'll need some endurance.

I'm sure you'll master this task.
Did you find the [plur]Seiren Treasure Chest[pl:"Chests"]?
That ought to be enough.

From the outside, they appear to be intact.
You're wondering what the Seiren Treasure Chests will be used for?

You'll find that out if you keep working for the Recruitment Office.
(You clicked on Instant Report[pl:"Reports"] in the Quest Journal and reported about the mission.)

(Click 'confirm' to receive a reward.)