Abel is a turn-based Japanese-style RPG set in a dark futuristic environment. The player commands Abel and his teammates from the headquarters, where they can rest, receive items, and prepare for the next mission. The missions themselves take place in large dungeon-like areas. Randomly appearing enemies must be defeated in first-person perspective combat with a rather standard system: characters either attack physically, use items, or execute special attacks that require "special points" (equivalent to magic). There is also an Auto option for battles.

In the beginning of the 21st century, the Earth has reached an unseen level of technological progress. However, the environmental damage has also increased beyond anything the human had imagined. It was then that the disaster occurred: a huge floating fortress appeared on the Earth's orbit, and the self-proclaimed "Beast Empire" of monsters began invading the planet. Soon, a whole continent was destroyed. Humanity was on the verge of destruction. Only a special unit of agents trained and infused with the latest bio- and technological achievements can stop the monster invasion. The leader of this organization sends a group under the command of the young soldier Abel to investigate a location where the previously sent team disappeared without trace...