The best places to look would be major online retailers like Barnes & Noble or specific manga-focused websites. Just do a quick search and you should be able to track it down. Also, check out some fan forums or communities for recommendations on where to find it.
The best place to start your search would be major online retailers that specialize in manga. Sites like Right Stuf Anime or Book Depository could have what you're looking for. Sometimes, you can even find rare or out-of-print volumes on eBay or similar auction sites.
In this volume, the story focuses on the characters' efforts to solve a complex scientific mystery while dealing with powerful adversaries. There are also some unexpected plot twists that keep you on the edge of your seat.
You could try looking on platforms like Comixology or Amazon. Sometimes local comic bookstores might have it too. It might take a bit of searching around though.