Theta Mindstones are the biggest craze to sweep the planet since the Space Hopper and Stephen just can't wait to get his hands on one. The meditation toys - created by former hippie turned entrepreneur Elliot Jackson - are fun, sensual and extremely addictive, and come with the promise that they will blow your mind.

But soon, The Tomorrow People discover that there's more to Theta Mindstones than meets the eye. And with Stephen fighting for his life, Elizabeth and John must face their deepest fears to unlock their secret before it's too late for the human race...

This is the fourth novel in Oak Tree Books and Chinbeard's series of The Tomorrow People.