On Rue Bosquet, a small street in Brussels, two identical buildings stand side by side. One is the home of the Tiempo-Lechner family, known for its long lineage of piano prodigies. Matriarch Lyl Tiempo presides over her renowned children, Sergio Tiempo and Karin Lechner, as well as Karin’s daughter, Natasha. At only 14, Natasha is already a busy performer who carries the weight of her musical heritage on her shoulders. She asks: What does it actually mean to be a pianist? If there is an answer, it is to be found in the house next door, at the home of the famous Argentine concert pianist Martha Argerich, who opens her doors and reveals an inner life that is still filled with uncertainty: At the age of 70, she is still on a quest for perfect technique. This unusual, very human documentary is filled with moments of extraordinary intimacy and exceptional music.