Momo at Théâtre Princesse Grace

One evening, Mr. and Mrs. Prioux shocked to find that a Momo moved home. Momo returned with his parents to announce their marriage. The Prioux, who have never had children, flabbergasted ...

However everything seems to prove that Momo is their son. Momo is it a pathological liar? Manipulative? Have Prioux forgot they had a child?