Astra Lost in Space Vol. 3 (manga)

After their nightmare on Shummoor, the group arrives at the third planet on their journey, Arispade. The planet has plenty of food, water and sunshine, making it just like a tropical paradise and the perfect place to relax. Even the lone wolf of the group, Ulgar, starts to open up! That is, until he suddenly pulls out a gun and threatens to kill Luca! Could Ulgar be the traitor the group has been looking for?!