The Description:
 In the second part of the story, which starts immediately after the end of the first part, but extends into the next ten years, Tomoya and Nagisa live together as a family. Tomoya has to endure several hardships that the family has been suffering from, mainly involving Nagisa's illness. However, just after Nagisa gives birth to their child Ushio, she dies, leaving Tomoya to fall into a state of depression which causes Nagisa's parents, Akio and Sanae to look after Ushio. Five years later, Tomoya meets Shino Okazaki, his grandmother on his father's side. Shino explains to Tomoya about his father's past and tragedy, similar to Tomoya's current situation after Nagisa's death. After hearing that, he decides to raise Ushio and acknowledge Naoyuki as his father. Shortly after Tomoya regaining his purpose of living, Ushio is struck with the same disease as Nagisa. Tomoya, Sanae and Akio struggle to save Ushio, with Tomoya retiring from his job, but all efforts are futile. In the coming winter, wanting to do anything for Ushio, Tomoya decides to take Ushio on a trip, but Ushio falls unconscious and dies shortly after.
 Tomoya's psychology is further developed in his dreams of a bleak world where small orbs of light float around called the Illusionary World (幻想世界 ,Gensō Sekai?). In the first few dreams of that kind, he sees a world which is devoid of all people except for one girl, whom is never shown in the original game's... (The material was taken from Wikipedia)