Private detective Tatyana Ivanova faces a difficult case this time - she will have to investigate the death of Oleg Solodovnikov's mother. An intelligent old woman, Elena Grigorievna, was discovered with a broken head in her own apartment by her grandson Sasha. Why kill an elderly woman and who could she open the door to? Tatyana Ivanova is going to look for the killer in Solodovnikova’s distant past...