To Ms. Sakuragi, who traveled abroad or had busy period for a year, we can interview at last.

If you want the impression more, althou it contains spoiler, read from lnk bielow. I accept any claims lol.

http://www.sf-fantasy.com/magazine/sasabe/?p=402

Day after day, Frontier was riding across rimless universe, but something aproached to Frontier....

Anyway, a higher existence, a supervisor of galactic cluster, gave the captain a trial and invited him to resolve a trouble. If he failed, he would be regard having no requirement to pass across galactic cluster. The trial was, ..., “Nobunaga's Ambition.”

Sound wave, radio wave, and gravitatinal wave. And also probability wave in quantum mechanics.

Here is a topic from waves.