Ferus, Book 6 in the Heku Series, continues to follow the Ferus Organization, a heku alignment that is struggling to become the 4th heku faction.

With the newly renewed tension between the factions growing even more violent, Emily struggles with the loss of past friendships. Chevalier and the Equites find themselves, once again, fighting to keep Emily with them, and their power brings the Valle and Encala to their knees, again wishing to renew the once strong alliance.

Emily finds friendship and purpose out on the island and only another attack brings her back to the palace, but not for long. Again the V.E.S. interferes, and when the island is no longer safe, she is forced to return to the palace.

Exavior crosses the line and breaks ancient rules set to keep the mortals safe from the ancients. Emily and Dustin begin a war of their own and the Equites become irritated with their constant fighting. When Dustin takes the arguing to new levels, the Equites Elders begin to lose their faith in the former Powan.

Another war in Council City pits the Equites against the other factions, and Emily's method of revenge even shocks the Equites.