Love Live RESTART

A man was suddenly transported back to the past, back into his younger body while he was just a High School student.
He decided to use this second chance to save his sister from dying, and his other friends. However, he also had to deal with his previous life's trauma and the pain he had endured.
A story about a boy trying to change the past. A story about a boy trying to fix his mistakes. A story about a boy trying to live happily with his sister. A story about a boy trying to find love.
Will the main character succeed in his goal? Or will he fail once again?
Only the future will tell.