Wash the dried black plums and take them into a pot. Add 5 cups of water and let it rest for 2 hours and strain. 

Put 8 cups of water and granulated sugar in a pot and boil. Add the dried black plum and lemon juice. After boiling for another 5 minutes, take the pot off the stove. Cover the pan and let it cool for 10-15 minutes to become tepid. 

Take it to the refrigerator to chill, wait for 1 hour and serve.