The word "télos" is an old Greek word, meaning "end" or "purpose", so it's no surprise that in the game Télos the last part of a round is what matters.
Télos is a trick-taking game in which you need to save your lowest card for the last trick. Winning the last trick gives you points, and in this case the points are negative. The first player to gain 32 points loses the game.
Saving your lowest card sounds easy enough, but the challenge comes from every player needing to play a higher card than the highest card already on the table in a trick. If a player can't play a card equal to or higher than that card, they must play their lowest card instead. Players therefore need to be careful which card to play when to tactically save their lowest possible card for last.