“Oblivio” is a Season 3 episode of the series, Miraculous: Tales of Ladybug & Cat Noir.  Based on the production order in the series directly, “Oblivio” is the 10th written and produced episode of Season 3. It is also the 62nd written and produced episode of this series, in total. 
Synopsis of Oblivio
Ladybug and Cat Noir are losing their memories, will they be able to defeat Oblivio so that the criminal can be just a bad memory?
Ladybug and Cat Noir have lost their memory … and the mysterious villain roams Paris. Will our amnesiac heroes be able to defeat Oblivio and turn him into just a bad memory?