Full story here: amazon.com/dp/B00T5GUOYM

As the dominant force in the galaxy, they were used to bringing new worlds under their control, but were blinded by their own success…

After coming into contact with a highly developed alien race, mankind was left with little option but to accept an offer that was impossible to refuse. Unable to meet a threat from an alien star system, it decided to cooperate with the alien race, not realizing that the Solar System was just one of the steps in a grand plan as old as mankind itself…