Got series 2 for my birthday yesterday, watched School Reunion, and got the idea for this.
Don't own them
DOCTORWHODOCTORWHODOCTORWHODOCTORWHODOCTORWHODOCTOWHO
After lying in the boot of Sarah Jane Smith's car for years, K9 Mark III encounters a miracle. He is not covered with an old tartan blanket anymore, he is sitting on a table in a café, while someone is mending snapped wires, and fixing broken connections. He takes a guess as to whom this is - it's the Doctor-Master. It isn't the one with the floppy hat and long scarf, who continually told him to be quiet, but it is his master all the same.
The Doctor-Master speaks to him. He has a task for K9 and because K9 is the Doctor's faithful pet, he will obey. There is oil for analysis. While he is analysing the oil, Mistress Sarah Jane defends his voice to a young man K9 doesn't recognise.
The substance is Krillitane oil. The Doctor-Master does not like this, but K9 is too weak to find out what happens next and goes back to sleep.
It is the next day. K9 is back in the boot. Someone banging on the top of his head awakens him from his sleep. It is the man who laughed at his voice, now inquiring if K9 has a lock-picking device. He doesn't but he makes (in his opinion) a perfectly reasonable suggestion.
"We are
in a car."
The young man doesn't get it, so K9 repeats it
until he does. Then the young man drives Mistress Sarah Jane's car
through the door. K9 doesn't know if she will mind but they are all
in danger, so maybe she won't. He is lifted out of the boot, and
then the man and a boy with glasses run off.
K9 trundles round until he finds the source of the noise and screaming. He is very weak but he is the Doctor-Master's faithful pet after all.
K9 goes into the hall and sees the blonde haired girl, the boy with glasses, the Doctor-Master and Mistress Sarah Jane being attacked by Krillitanes. It is his mistress who sees him first and screams "K9!"
He offers a suggestion. "Suggest that you engage running mode, Mistress!"
Everyone takes a hint, and K9 starts shooting lasers at the Krillitanes. But he is weak. His batteries won't hold out for long, and he must get out too. K9 hangs his head. He has tried and failed to do his task. But he hears his master's voice so he trundles out into the hall after him.
"Come on K9! Good boy!" His master encourages him on, and they end up in the school kitchen.
K9, with his über advanced brain, knows that the only way to save them all his to blow up both the vats and himself. He puts this idea forward, and the Doctor-Master shoos the assembled company out of the back door, and says a final goodbye to his faithful friend and calls him a good dog. K9 agrees, and positions himself beside the vat. When the Krillitanes come in, he blasts the vat, and Finch says his last words "You bad dog."
The school blows up. K9 is killed. Sarah Jane sobs over his sacrifice. K9 doesn't know his mistress is crying, but what he does is that the Doctor-Master is fixing him.
24 hours pass. The Doctor-Master says goodbye to Mistress Sarah Jane one last time, and the TARDIS vanishes.
"K9!' His mistress is delighted to see him. K9 explains that the Doctor-Master has rebuilt him, and he is better than ever.
Mistress Sarah Jane heads home, K9 following her.
Because, after all, they do have work to do.