The ruins of the former castle are situated on the cliff overlooking the market town Planina pri Sevnici. The core of the ruins is Romanesque, while the southern castle wall is Gothic. The entrance and part of the defensive wall in the north-west are from the Renaissance period. The heart of the castle was a powerful palladium which back then measured 38 m in length and 15 m in width. The castle was protected by a powerful defensive wall, the base of which was 3.5 m wide and a defence tower on the western side, protecting the original access from the south. In the 14th century, the chapel of St. Pancras was added to the eastern side of the castle. The Roman wall still holds the original windows which were made at a later stage. The lower part of the wall is at some places built in the form of a herringbone or cereal spike (opus spicatum pattern), which is quite interesting.
A storage granary with a vaulted basement which has remained preserved until today was built west of the castle in the 16th century. At a slightly lower location than the castle, there is a cellar built into the bedrock, with a partially preserved entrance arch.
In the mid-14th century, the nobility of Planina came under the ownership of the Counts of Celje, who owned it until the extinction of the family line in 1456. Legend has it that the two people who spent most of their time in the castle were Frederick II and his second wife Veronika Deseniška. In 1456 the castle passed to the Habsburgs, who hired it out to various families until the Archduke, Ernest of Austria sold it to a great noble family from Lower Styria and Carniola named Moscon. They retained possession of the castle from 1593 to 1769. Thereafter, it was owned by the Prothasi and Gorišek families. The last lord who lived in the castle was Gustav Bloome. In 1882 the roof of the castle was removed, and with the passing years, the castle fell into ruins.
Various events and weddings are held at this site nowadays, and the castle granary can be rented for receptions. The place offers a beautiful view of the surroundings, which is even nicer from the newly built lookout tower.