This 96-page hardback book contains:

- A deluge of background information on the mysterious Idoneth Deepkin, including their arcane origins and aquatic way of life.
- Ethereal artwork that displays the majesty of the Idoneth Deepkin
- 18 warscrolls and pitched battle profiles for Akhelian nobles, soul-starved Namarti Thralls, and vicious sea beasts like the Allopex or Leviadon
- Rules for the 6 primary Idoneth Enclaves, plus command traits, artefacts of power, spells, and battle traits such as Forgotten Nightmares and Tides of Death
- Path to Glory campaign rules that allow you to plunder the Mortal Realms in Idoneth soul-raids, plus 3 warscroll battalions for use in narrative play
- Matched play content including 4 grand strategies and 6 battle tactics to unleash against your enemies
- A showcase of abyssal Idoneth Deepkin miniatures assembled in the colours of their Enclaves, alongside guides on how to paint them yourself