The kingdom is under siege, a dragon lives nearby in the cave, recently it was accidentally woken up when they gave a salute in honor of the Princess's birthday. The flying monster did not get enough sleep and was very angry at all. He flew to the palace and threw colorful balloons at him. It seems harmless, but there are so many balls that the dead walls of the castle can collapse and turn into fragments. It is necessary to shoot balls from cannons, but according to a special principle, collecting together three or more identical ones. Otherwise, nothing affects them, because the balls are magic and are called Dragon Bubble.