From the instructions: "The round ends when: One of you has no cards left in your hand..." or "...should draw a card, but the draw pile has been used up." And further: "If you are currently playing a card effect or an event, you still complete this as far as possible. The round is over if one of the conditions for the end of the round is still fulfilled afterwards" and finally: "It is possible that several players end the round at the same time due to an event".