Married but separated couple Matthias and Anna, marital wounds still open, get together to plan their son Lukas' birthday party. When, at the end of the party, little guest Julius isn't picked up by his parents, a rapid chain of events takes place. First Matthias just wants to get rid of Julius, but later the helpless little boy awakens Matthias' protector instincts and opens his eyes to his own son's needs.