Totally unexpected heart-wrenching story

Rating: 7/10 (21 September 2016)

Two children met and shared their dream, who inspired by a famous explore Charles Muntz who ended up being accused of fabricating an exotic bird which he claimed he discovered at Paradise Falls. The both of them, Carl and Ellie eventually got married, and their marriage life seemed to be rosy. However, after Ellie died and Carl was left out alone, this elderly widower decided to fulfill his dream that promised with his wife by turning his house into airship using a thousands of helium balloons, and traveled in the air with a young boy, Russell, who followed Carl.
The first 10 minutes described how they met, married, and how miserable Carl's life after he lost his wife, which was heart- wrenching. I didn't expect the story was going to be happened like this because this is meant to be a family movie and it's Pixar's. Not only have Carl dealt with bereavement of his beloved wife, they have experienced Ellie's infertility. The boy, Russel, has a complex family background. Kevin, who they met at Paradise Falls, seemed also be a single mother, assuming Charles Muntz may have killed the father. Things were going on, which were totally out of expectation, and shocked me. Is that necessary to have that much traumatic events with the characters?
The rest of the story was more positive impression where the protagonist was struggling with happening he encountered, overcame while he was struggling, and the bad guy should be punished. The ending wasn't so bad, so overall I was sort of satisfied with the story.