Click Lupin for info about Lycanthropy, and collect the Dittany from between the two. Move around the shackles behind Lupin and zoom in.
New from J. K. Rowling:
Move over Harry’s wand to make the puff of patronus disappear. Pick up the yellow thingy above Sirius, which is Spine of Lionfish. The round pebble next to his head can also be picked up; it’s… a pebble. Good luck with that! Then, pick up the Tubeworms sticking out from the lake.
-Spine of Lionfish