A computer thriller from the Level 4 series When Ben finds a ring that can be used to read minds, he is initially totally thrilled. But then this ingenious invention falls into the wrong hands. Together with his friends Frank, Mirjam and Jennifer, Ben soon finds out that the ring works by means of a sophisticated computer chip. But then this precious piece falls into the hands of Kolja, of all people, their arch-enemy. Kolja is up to no good and wants to use the ring to steal the school computers. It's not easy to get the ring back from Kolja, because if you can read people's minds, you can't hide anything from them! When the four of them finally succeed, they set out to find the inventor of this ingenious, but at the same time extremely dangerous invention. However, not to return the ring, but to the inventor to.