After Rose gets a distress call from The Doctor, she gathers a group of the Doctor's greatest allies, one of which is Sarah Jane Smith with K9. He then appears when the Companions arrives where the Tenth Doctor is. K9 then appears when they all say, "okay", after the Doctor says that he will take on the Time Lords. K9 then appears when everyone is surprised after the Doctor says that they are going to fight the Daleks. A Dalek then shoots them. K9 then appears at the end when The Narrator comes in and does a cliffhanger ending.
The 11th Doctor is bored on the TARDIS. He is playing with a ball. K9 appears and the Doctor hits him with the Ball. K9 fizzes and then his head falls off and he catches fire. At the end of the video, the Doctor regenerates into the 12th Doctor. K9 appears again and the Doctor kicks K9.
K9 first appears on the TARDIS, where Clara and K9 are running from a Dalek. K9 then appears at the end, when the Clara, the Doctor, an Adipose creature, Handles, K9, and the Dalek arrive at the TARDIS console.