S1·E22 Heaven's Gate

The Countess tells Isamu more about the past and how she first met Enkidu. At that time, research at Heaven's Gate was in full swing, and the Countess was working there as a scientist. However, one day a mysterious life form was discovered; shortly thereafter, all experiments were halted, and Heaven's Gate was completely shut down within a year. This dealt a heavy blow to all the staff, especially since the very event Enkidu had predicted was coming to pass. All of this was overshadowed by a terrible accident known as "Twin X." During the incident, the Countess fell into a coma for several years, and from that point on, she made it her mission to ensure the truth behind the event was uncovered.