Next to the Resurrection Summer Cathedral, on the eastern side, stands the second majestic warm church dedicated to the Holy Trinity. This stone church with three altars was built in 1821 thanks to the efforts of Abbess Mavrikia Khodneva and the sisters of the convent. It was erected on the site where a wooden chapel once stood, serving as the burial place for the royal prisoners, princesses-in-nunhood Evdokia and Alexandra.

The church has the shape of an elongated square with semicircular projections to the east and west, which are slightly lower than the main building. On the southern and northern sides, there are pediments supported by four half-columns. Above the semicircles are wooden cornices resting on sixteen stone round columns. The roof of the church is four-pitched, covered with iron over wooden rafters. Above the church rises a large dome in the shape of a cauldron, with a neck surrounded by ten small columns and a small dome topped with a cross.

The entrance to the church is located on the western side and begins with a spacious stone porch that leads to a small semicircular narthex. It is separated from the main space by a solid wall with double doors. The interior space of the church is a square with a semicircular projection to the east. The plastered wooden ceiling is supported by twelve wooden columns clad in iron. These columns also support large choirs located along the northern, southern, and western walls. The choirs contain two chapels: in honor of the Mother of God of Vladimir on the southern side and of All Saints on the northern side.

The altar is separated from the main space by a solid wall with a large opening where the iconostasis is located. It is also in a semicircular shape, recessed into the altar, and decorated with carvings and gilding. The upper cornice is supported by eight round columns painted blue, while the iconostasis itself is painted lilac. The royal doors are made of wood and adorned with gilded carvings; in the center is the Annunciation of the Mother of God in a silver robe with multicolored stones. Above the doors is depicted the Holy Spirit in the form of a dove, and above that, the Last Supper and the icon of the Resurrection of the Lord.

The restoration of the cathedral was completed in 2014. Work was carried out to restore the facades, roofing, dome, installation of crosses, restoration of brickwork, arrangement of the foundation, painting of the facades, as well as recreating windows and doors.