In the comedy Party Harder: Summer Massacre, a group of friends from the first part will return. They have already recovered from their terrible party and in the summer they will go to the "Ibiza of the East" - to the Macháč lake, which is a legendary place full of parties, music and free sex. They are trying to earn money for the golden nail of the summer - the Summer Massacre festival, from which they promise the experience of a lifetime and, of course, holiday sex. Will they enjoy the summer or fail miserably and face humiliation, involuntary celibacy or even Serbian militias?