Its a 11 minute ova, including OP and ED. Artwork and such is the same as the show which is good! It just shows a fun little interaction between some characters taking place after the last episode. They made a small change for the OP that that was more than enough reason for me to enjoy this ova, and the name was a fun little reference. It is just a OVA with no significance to the characters or plot really just a good time. I would recommendwatching this if for nothing more than the OP (the change isnt that great to be honest so dont get your hopes up) but its fun and a worthwhile watch if you enjoyed the characters