Stardust

Nova Hoshikori is a 14-year-old teenager, who struggles in life. His parents fight a lot, he moves once every year, and he's had to grow up so much earlier in order to raise his 9-year-old sister, Sakura. He doesn't really have a goal in life yet; he just wants to live through everything.
One summer, he's told he won't be moving again. His parents divorced, and he and his sister stay with their mom. His mom barely scrapes by, working nearly 24/7 with few breaks to sleep. Nova prepares to spend the next several years of his life alone, spending his time taking care of his sister. He soon, however, makes a few new friends, most importantly of which is Amy Tensiro...