Generally it is about possible invasion on Poland by Warsaw Pact armies in 1980. The reason for that was the soviet policy trying to keep the communist power over all the communist countries. Also it was to be a part of an attempt to destroy the Solidarność organisation in Poland. The Czech army was planned to entry Poland from the South and occupy the bordeline area in order to protect the communistic authorities there. Also if there would be the Polish Army units which could revolt when the USSR would step into Poland. The operation was coded as "Karkonosze" ( Giant Mountains) and , fortunately, has never gone through.