This picture is from which season and episode of The Horned Detective

This picture should be a screenshot from a New Year's short film or something by Devil Horned Detective, or it might just be a poster.

If you want to talk about which episode it is, it is the twentieth episode of the second season of The Horned Detective, episodes 45 and 46, the end of the bizarre maze case.

About three-quarters of the way into episode 46.

The general plot is that Qi Letian accidentally discovered his old uncle's secret room and found a "treasure map". Qi Letian, Jingjing, Xiao MU, photographer and Masked K went to the dense forest to explore, but were blocked by Ya Yue and others on the way! Phoenix Chicken showed up in human form and discouraged Yayue from aiding the evil deeds, while Yayue also felt timid about the devil horns on Qi Letian's head... Late at night, Qi Letian and a group of others came to spend the night at the "Mute Sound Shrub Garden". The Lord warmly welcomes everyone. When everyone was full of wine and food and fell asleep, the owner of the garden took off his disguise and found out that this was a trap set by Dorothy! Qi Letian seemed to see his evil self calling out to him in his sleep. When he woke up, he felt something was fishy and called everyone to escape from the shrubbery. At this moment, the wall of the shrubbery was changing slightly. Qi Letian and others were trapped in the bushes and were rescued by Huo Xing who was passing by. A few guys made some noise (singing the latest episode "Someday" while wearing the clothes pictured here) and defeated the bush's, um, "monster".

That's about it. If you have any questions, you are welcome to ask at any time.