'The Mother of the Seas is sick of humans using the oceans as a junkyard, so she decides to give the land dwellers a taste of their own medicine. Prepare for an unbelievable underwater menace that threatens to destroy the entire world!'
Source: Publisher's blurb.
'The Super Sidekicks just saved the world and now they’ve been invited to join H.E.R.O. – the Heroic Earth Righteousness Organisation – an exclusive club for the planet’s most famous superheroes. But before they can become members, the team must pass the hardest challenge in the universe, a test so scary and difficult only the truly heroic can survive.
'The Super Sidekicks are back! Prepare for another amazing adventure from New York Times bestselling Australian author, Gavin Aung Than.' (Publication summary)