Family expectations
As she looks for her mother's legacy among her family, Grace discovers that the entire family has expectations for who she should be, and what her cultural identity is. But Grace doesn't feel that sure about her cultural identity, especially since she was forced to move so many times to different countries.
The family expectations end up allowing Grace an opportunity to forgive her mother, and all the unfair expectations Grace was given as a child, by her mother, and by her family in general.
Peace and loss
The goal of the book is accomplish peace, given the unfortunate death of Grace's mother. This process is extremely complicated, and she ends up in the throws of existential dilemma. She can't figure out who she is, and the answer is only found when she realizes that the truth of the matter is that the family put unfair expectations on her, causing a self-esteem problem.
Grace finally heads toward a sense of peace when she can honor her mother's memory, while still being honest about ways that her mother harmed her. In other words, the book is about accomplishing peace through honesty and forgiveness.
Moving, immigration, and change
Many families move these days, but Grace's family moved from China to Singapore, then to Malaysia, and eventually, Australia. Needless to say, Grace's sense of "home" is pretty much non-existent. The only constant thing in her life is that her life is constantly changing, often in drastic ways that would be hard for anyone to handle.
These issues raise an interesting question about cultural identity, and Grace wonders what her life is supposed to be like now, since she has seen so many different ways of life, given her newfound independence.