Aren and his fellow angel brethren stopped Lucifer and the angels who chose to follow him from invading Heaven. The Father then cast them into the deepest and darkest part of the Earth. In the mean time, God the Father restored the Earth and built a garden called Eden. He has assigned different angels to do different tasks. One of the tasks is to take care of the beings the Father created. He calls them humans.
Lucifer managed to get to the Earth's surface. He made his way to where the humans live, the garden of Eden. He leads the humans away from God the Father and as a result, they get banished from the garden. This is when they the angels serving the Father discover Kryvo, one of the angels who fought against Lucifer, has gone missing.
God the Father gives Aren a mission: find Kryvo and bring him back to Heaven. This mission will force Aren to examine the real motivation behind serving the Father as well as answering an important question: did he pick the wrong side in the conflict between Lucifer and God the Father?