María and Daniel are a young couple who are expecting their first child. To help María in the last weeks of pregnancy, her sister Sara sets up with them in the house. The cohabitation of Sara with the couple rekindles the love she always felt towards her brother-in-law. But Daniel is also attracted to her, something that does not go unnoticed by María. Daniel and Sara can not hide that they love each other, but neither can they hide another common feeling: that of not hurting María.