The Secret of Mountain Lake () is a 1954 Soviet adventure film directed by Aleksandr Rou.
In the fields and gardens of a large village in the mountains of Armenia there is a severe drought. In the past, there was a legend, according to which a river flowed here, but a monster named Deve hid its waters from the inhabitants of the village. Suddenly the village is visited by a group of geologists. Residents of the village of Kamo, Nikita and Grikor decide to help them.