INFO:

A Photon Rocket designer, Dr. Kasuga, was killed by Alien Tigris who aim at the design, and burned his house. However, the Kasuga siblings, consisting of 5 children of Dr. Kasuga, trying to hide the blueprint of the rocket's engine, and the second son Koji Kasuga will be able to transform into Silver Kamen (using Silver Power). They decided to fulfill their father's last wish to complete the construction of Photon Rocket. At the same time, they traveled throughout Japan to meet with their father's acquaintance while dealing with various enemies such as aliens who disguised as civilians. All the efforts of the siblings show results, the rocket is completed and successfully launched into space. When in the destination, Alien Southern attacked, then destroyed the rocket. At that time, Silver Kamen were overflowed with Photon Energy and evolved to Silver Kamen Giant, and defeated Alien Southern. In this way, the sibling, who has gained a new power, making a new rocket development with the help of their father's favorite students, Dr. Tsuyama, and burns the spirit to fight with the threat of giant aliens.