Really interesting. Honestly, the whole history part of Japanese ships might be interesting for ship nerds (and for me as well who isn't one) but the more interesting part is how they deal with this phenomenon in front of them. I think they might have come to the realization too soon but it doesn't feel that way towards the latter half. Some simple time travel concepts were thrown in there so it's not exactly the most complicated plot. Let's hope it unfolds in a more spectacular manner.