Samira and her family move into the oldest smart house in Germany, which has been empty for more than 50 years after the mysterious death of its owner. The new tenants come to love Cassandra's virtual assistant, who was developed in the 1970s. Sensitive and attentive, she helps the family settle into their new place and takes care of household issues. Gradually, however, the yi assistant becomes increasingly insistent that the house be run only according to its strict standards.