The Isolator Novel Volume 4 is written by Reki Kawahara.

After infiltrating the Ruby Eye hideout, Minoru Utsugi falls into a deadly trap but narrowly escapes thanks to the Refractor's desperate sacrifice. Though her gambit saved them both from the Liquidizer's scheme, Suu paid for it dearly, leaving her in critical condition. After this tragedy, Minoru must find his place in this new, dangerous world again but his enemies won't wait now that the Stinger has arrived, ready to crush the Syndicate!