In 2071, roughly fifty years after an accident with a hyperspace gateway made the Earth almost uninhabitable, humanity has colonized most of the rocky planets and moons of the Solar System. Amid a rising crime rate, the Inter Solar System Police (ISSP) set up a legalized contract system, in which registered bounty hunters, also referred to as "Cowboys", chase criminals and bring them in alive in return for a reward.

Ten years ago, a mysterious spatial anomaly now known as "Heaven's Gate" appeared in South America, shortly followed by the opening of "Hell's Gate" in Tokyo altering the sky and wreaking havoc on the landscape. The real stars disappeared, replaced by false stars. During this time, people possessing various special abilities — called "Contractors" — emerged, each capable of different supernatural feats. Following the disastrous Heaven's War, the United States lost its dominant position as a superpower to a mysterious organization named the Syndicate. The story revolves around a Chinese contractor codenamed "Hei" as he undertakes various espionage and assassination missions in Tokyo.

From the moment Máxima Zorreguieta appears at the Dutch crown prince’s side, she finds herself in the spotlight. When Willem-Alexander asks her to marry him, the past catches up with her. Heated discussion erupts about her father’s political career in the Videla regime – a discussion she never faced in her own circles. What allows this Argentine to finally thrive at an old European court? And how can Máxima stay true to herself without giving up her family – or do these things not go together?

During the traditional carnival celebrations, the dead body of a young girl is found near the small town of Bellinzona, in Southern Switzerland. The officers engaged in the case find themselves investigating crimes rooted in a past full of shadows.