The scientists count it among the ten most dangerous volcanos of the world – Merapi, the fire mountain of Java. Alone in the past hundred years, it has claimed more than 1,500 victims. The risk of a new, heavy eruption is quite high and it possibly could have a global impact. Meanwhile, volcanologists from all over the world observe every movement of Merapi. Currently, German scientists have detected an until now unknown tectonic destruction which possibly could play an important role in the volcano’s activities. The film team accompanies the researchers on their thrilling expedition to the 3000m high margin of the steaming crater.