The Crystal Crescent

Raki and Tando are on a mission to find telotion, a rare substance which creates huge amount of ozone when heated, in order to repair the ozone layer of their planet. When they crash-land on an unknown planet, they not only find telotion, but mysterious blue creatures who take over Tando's mind. What do the creatures want, and will Raki be able to find out and save himself and Tando? Suggested level: primary, intermediate.