Searching for Sylvie Lee by Jean Kwok

Sylvie Lee is the eldest daughter of a couple who moved from China to NYC in search of a better life. When Sylvie's mother realized she was pregnant with her second child, she took Sylvie to Amsterdam to be "temporarily" raised by cousins there. Temporarily ended up being 7 years. Sylvie loved her Chinese grandma and her cousin Lukas but otherwise life in Amsterdam wasn't easy. Then she goes back to NYC and doesn't really fit in there either. Sylvie becomes an overachiever to compensate for never feeling like she belongs anywhere. The one bright light in her life is her little sister Amy.

When word comes that the grandma in Amsterdam is dying, Sylvie flies back and re-immerses herself in the lives of the people she knew as a child. Then Sylvie disappears. Amy flies to Amsterdam to find her sister and discovers that she didn't really know Sylvie as well as she thought she did. It's an engrossing story of clashing cultures, secrets, and family love.

As a side note, I also loved this author's Mambo in Chinatown.