Sasaki and Peeps, Vol. 6 (Light Novel)

"With the Herzian succession dispute now settled, Sasaki and Peeps head back to modern Japan just in time for a new case at the bureau. Along with Futarishizuka and Hoshizaki, Sasaki is tasked with investigating a series of recent UFO sightings, and for once the assignment appears to have nothing to do with the otherworld. Exhausted from their earlier ordeals and lacking clues, the crew decide to take it slow and leave the heavy lifting to the experts"--