''First day back at school'' is the first episode of Sunnyside school.
Combo is about to film another gaming video for his channel, but his mom calls him. He runs as fast as he can to get to the school bus, and eventually arrives there. Combo then explains that about his ''first day of school routine''. Big Gil arrives at the bus and so does Peck, with the latter explaining how he got to Combo's grade at a younger age. Then they talk about how they have the same teacher.
As they get into class, they meet Alpha lexa, who arrived early. The teacher is revealed to be Ms. Lucille, who is a seal and tells the students that they will introduce themselves and tell her a special talent that each of them have. Gil is nervous, and is called first. he then explains himself, and then he farts, causing every student except Alpha to laugh out loud and say that farting is his special talent. Gil leaves the class crying, and Alpha explains to Combo that he shouldn't laugh at Gil's farts. Combo then runs to Gil in the hallway and says jokes about his farts, with Gil explaining that it is not funny, and leaves the hallway.
It then cuts to Combo and Peck in science class, with Peck explaining that he has an ''evil twin'' in the class who likes to roast him. The teacher is revealed to be Mr. Zumi, a hedgehog. he explains that everyone should introduce themselves. Peck's evil twin, who is revealed to be named Peter, is the first to introduce himself. Peck then falls on the floor unconscious.
Then it cuts to Combo and Alpha in art class, with the latter being explained how there are two pecks and that one of them fell unconscious, and that the school called his mom to bring him popsicles. The art class teacher is revealed to be Mr. Drill, a lion, who then sees everyone's paintings and says that they are inspiring. he then looks at Combo's art, which is revealed to be Gil farting.
Then Combo and Gil are in math class, and the latter is still angry at combo. The math class teacher is revealed to be Ms. Lillypad, who asks some questions that no students know the answer to, with a cricket named Wicket who makes the cliche chirping noise. Then the two are in recess, and are fighting. Gil then leaves and later Combo is hit in the face with a football, but it is Dark titan who kicked the ball.
All the students are in history class, and the teacher is revealed to be a rhino named Mr. Coach Pat. Dark titan enters the class late, and is forced to do push-ups as a punishment. When he is doing push-ups, he occasionally farts, this causes everyone, even Gil, to laugh at him, Combo and Gil then put aside their rivalries and become friends again.
- This episode debuts the teachers.
- It teaches kids that farts are sometimes funny.
- It has been viewed over 3 million times.