A/N: A ridiculously old story featuring the little quarter-Timelord Kasterborous "Kaster" Tyler, who belongs to Person-without-a-FF.N-account.

Bang. Bang. Pause. Bang.

Of course. This blasted child's hands could reach anything despite its location in the room, thought Jackie Tyler, making her way to the room from which these sounds were heard. Their source was usual. An eleven-month-old baby boy with sparkling dark brown eyes and a shock of dark hair sticking up (a perfect mixture of his parents - both in appearance and habits: Jackie had a suspicion that he would become a walking explosion like his dad when he grows up, but still had a hope he would have his heart in the right place) was standing in his bed, holding on its railing with one hand. The free chubby fist was clutching - guess what? - the silver instrument with a blue light on the top, and the child was cheerfully hitting the railing bars with it.

"What are you doing, Kasterborous Philip Tyler?" Jackie yelped. "For how many times have you been told that you shouldn't take daddy's sonic screwdriver?"

"So-onee", Kaster replied, and Jackie froze for a moment - this was the first normally (well, almost normally) pronounced word heard from him. But she quickly collected herself, freed the poor tortured screwdriver from the grasp of tiny fingers and put it onto the shelf where the child couldn't reach it.

"You little wrecker, you've already broken the door handle, and I still can't understand how you managed to do it", Jackie announced. "Why can't you behave like Tony and play nice?"

"Want", Kaster said clearly.

"Even if you are my supercool-Timelord grandson, I won't give it to you until you are big enough to understand what you're doing".

"Want sonee", Kaster repeated, leaning over the bed's railing in trials to reach Jackie.

"And you just know it is forbidden! I don't want you to get more traumas than your heart surgery one!"

"WANT SONEE!" Kaster squealed, waving his little fists while Jackie pushed him back for him not to fall over the obstacle.

"Physical abuse won't do anything, Kaster. Now stay here".

"Want sonee", Kaster responded in quieter voice, his expression changing to the "lost kitten" one. Oh dears, Jackie thought. What is going to grow up out of this little rascal?..

The result, as they say, was more than any expectations. Despite almost everyone in the family being worried about possible consequences of the surgery operation after which Kaster's second heart had been removed (it could have been worse: Handy had a theory that having two hearts and a singular vascular system could make the child grow up too fast, though he had no proofs of this), the boy was perfectly fine. The only reminder about this was a large scar on his chest, but nothing more.

Curiosity is natural, so every child in the playground would abandon their having fun and gather around Kaster when he came there. His pockets were always full of gears, weirdly looking instruments (as a rule, secretly stolen from the rubbish bin where Handy and Rose usually threw the hopelessly broken or useless - for Torchwood where they worked - devices), wires and such-like trinklets, and he would always patiently sit on the bench, having covered half of it with his pockets' contents (how did it all fit there?!), and try to make something out of it. That happened all the time when anyone who was together with Kaster received an urgent call (such things happened quite frequently), and there was an agreement - if that happened, Kaster was accompanied to this playground and left there.

"What you doing, Kaster?" Annett Simpson asked.

"Da has sonic scwew-dwiwah", Kaster replied - it was complicated for his three-year-old tongue to pronounce the word "screwdriver" properly. "I wanna better. Bad Mass-ta had laser one, I wanna two in one". Having chosen the smallest hankwrench from the pile of instruments, he began fixing something on the hybrid-like gadget in his hands, having made a bunch of sparkles dash out of its end.

All of a sudden Kelly Finnigan turned around and yelped:

"Oh! Smash, Dash and Cwash!"

Smash, Dash and Crash were commonly used nicknames for the three bullies who would always spoil the game for the kids like Kaster. If they were around, at least two kids would come home in tears and almost everyone getting an offence. This time they already came with a victim - it was a boy with a mop of almost white curls who was lifelessly hanging in Smash's grasp.

To everyone's surprise, Kaster didn't run though he had been told about them. On the contrary, he pushed all his gears into his pockets, stood up and walked to them.

"He's toast", Ian Trumper mumbled.

Meanwhile Smash, Dash and Crash were having loads of fun, not letting the poor child go, but they were interrupted. By whom? Not by a grown-up. Grown-ups would tell them not to play ("torture", as they called it) with little kids, but never do anything, and this time another child was cheeky enough to interfere in their fun.

"Let him go", a squeaky, but full with sureness, voice said. A small boy, his arms crossed, was staring at them. Smash, Dash and Crash cackled, and Crash, who was their unofficial leader, expressed the opinion of all of them:

"And what are you going to do? Pinch us with your undergrown fingers?"

"Let him go", Kaster repeated. "You bonehead wodents! Pway with someone like you and let him go!"

Smash almost dropped the curly-pate to the ground. Now there was another one to play with, and this game could be even more interesting. There's a rule in any game: you must have fun. You, not the ones whom you play against.

"You moved your piece", Kaster grinned evil-like, showing his tiny teeth and sneakily searching for the handle of the tool he was about to use in his pocket. "My turn!"

In a second he was running away from the three who were enermous compared to him and supposed that catching Kaster would be the easiest of tasks, but there was something else. When Dash attempted to grab the child, Kaster threw himself onto the ground and curled up in a ball, so Dash tripped over him, and, as a result, all three were on the ground. Kaster didn't lose time - he snatched the water gun out of his pocket, and the stream of cold water hit Smash in the most delicate part of his body with mortal accuracy.

"Why you little!.." Smash roared. All children, except the ex-victim - he was hiding behind everyone's backs, still afraid - exploded with laughter. No wonder, now the "giant" looked as if he peed himself. What a shame for a big boy! Kaster blew the imaginary smoke stream off his weapon's tip and stuck it in his bottomless pocket, ready to use another gadget. Now it was Dash's turn to get his punishment.

Having waited for a moment when the next one was about to get him, Kaster chose the aim and pressed the button on Handy's stolen (again) sonic screwdriver. Actually he had planned to use it as a solderer to join the gears together, but here it was a special case. In a moment there was a buzz, Dash's belt got unbuckled, and he collapsed onto the ground, having got tangled in his own pants which were now messed around his ankles.

Now the final task was to teach Crash a lesson. This was the most complex task: Crash was the strongest and the largest of the three, and this is why he was their leader. It was a perfect situation to try the result of Kaster's effort out, because classical panty tricks wouldn't help in his case. Having made the bullies follow him again, Kaster got the third gadget out and...

KABOOM!

The "prototype" exploded like a fine grenade, having left miserable remains in Kaster's fist (thank goodness it didn't hurt him), but it worked. This was too much for the three bullies... In a second they were gone, and Kaster decided to meet their ex-victim. Paying no attention to the kids watching him with popped eyes, he made his way to the white-haired boy.

"I no want hurt you", he said. "Imma Kaster. And you?"

"Bertie", was the quiet reply.

"Why they hurt you?"

"I cannot beat them", Bertie whispered. "No running, no bouncing. Mummy says I have sicky heart and shouldn't do it... You so brave".

Kaster blushed. And there was already a guess building in his head.

Jackie gasped when she saw her grandson - his face, as well as hair in front, was covered in soot, pants were torn on his knees (and one pant sleeve was soaking wet - Kaster had put the water gun into his pocket in a VERY unsuitable way), the front of his shirt was burnt and there were some fresh scratches on his hands, covered with machine oil.

"Now, you little wretch, tell me nothing until you look like a human, not a piglet!" she ordered. "Pockets inside out!"

"Granny Jackie!" Kaster shouted. "I wanted to pwotect Bertie fwom bullies!"

"Tell me nothing, young man!"

Luckily voices of Handy and Rose were heard from downstairs right when Jackie was about to get Kaster's pockets (she wasn't worried with the fact that dimensional transcendentalism worked here) empty with force. Kaster hurried there, hastily explaining:

"Mummy! Daddy! Imma not guilty!"

"For TARDIS's sake, Kaster, where did you climb from?" Rose asked upon the sight of her son. Jackie was next to speak:

"This walking explosion says he wanted to protect someone..."

"Yes, I did!" Kaster squeaked, trying to speak louder than her. "I did! Smash, Dash and Cwash towtu-ed Bertie, and I taught 'em a lesson! And Bertie has sicky heart..." He thought for a while. "Daddy, can my second heart be given to him? You told me itssa all fine, and Bertie is so very weak..."

Hardly paying attention to Jackie's lamenting about Kaster's messy appearance and his activities, Handy sighed. The child had his heart in the right place, despite his being such a small catastrophe.

"Kaster, it's up to his doctors to decide what to do with his heart", he said honestly.

"But your bwro Doctor!" Kaster wasn't going to calm down.

"All right, Kas, I promise we'll do everything we can if you tell us all", Rose interfered. "But you have to do something first. Return the sonic screwdriver". Kaster obeyed, though he couldn't hide it that he would rather leave it in his bigger-on-the-inside pocket. "Next time don't steal things from the garbage. If you want to make something, ask me and Daddy, we will help you".

"Really?"

"Really-really. And now go and get clean, you look like a pipe-cleaner!"

Kaster hasn't seen Bertie for quite a long time, but when he finally met him, it was already autumn (the bully accident had taken place in the beginning of summer). Bertie looked as if he had been locked inside forever, and at first Kaster thought he wouldn't recognized him, but he did.

"How's life, Bertie?" Kaster asked immediately.

"They replaced my heart", Bertie replied. "It's fine now. Doctor said he never saw another heart a-dap-ting so quickly! Mummy said it was like a miwacle!"

Kaster's mouth widened in a large smile:

"It's mine!"

"Huh?"

"They put my heart into you! I know it, I feel it!"

"But..." Bertie's face crooked with surprise.

"Ask my Da to explain... So now we're bwrothers in hearts?"

"Seems so".