His chocolate eyes focused on the only photograph he had of his father, sitting on the steps of the TARDIS, David sees how happy his parents looked, how one man destroyed everything.
Mackie did what any father would, protecting him and his mother, at the expense of his life, and after tomorrow, he'll have peace, knowing his work wasn't in vain.
"Oi! What gives hiding in here?" David heard Catherine barging into the TARDIS a look in her dark eyes as she stared at David while he adjusted in his spot on the steps, a bemused look on his face.
Marching over to him, Catherine chided him for hiding, but he insists he wasn't.
Looking over his shoulders, Catherine sees the photograph in his hand, and her anger softened.
"Because of him, I never knew my father and my mother never remembered him," David bitterly said as his chocolate eyes fell to the photograph in his hand.
His father's desperation keeping them safe from the Master resulted in him growing up with a father and his mother losing her memory.
Slowly gesturing her hand, Catherine pointed out, "It... worked didn't it… he didn't come after you two."
It wasn't something Catherine wanted to say, but it was the truth, despite his death, Mackie's sacrifices ensured the Master didn't find David and his mother.
Seeing her point, David slowly nodded as he admitted that she wasn't wrong, because of his father's actions, they lived in relative peace.
Seeing the dejected look in his face, Catherine insisted that David shouldn't worry, he'll kick the Master's arse and then some!
"With his mind alone, he done more than ruin countless lives, Cat, who knows what he's capable when he's complete," David brought up concerns that they're underestimating someone like the Master.
Shaking her head, her tied-back red hair stiffly moving in the breeze, Catherine lightly jabbed David as he stood up to look her in the eyes as she insisted, "You'll kick his arse!"
He may think differently, but Catherine believed in him, and while David's touched, despite their differences in the past, he reminded her the possibilities of him dying.
"Possibilities, schmolities, I've seen you getting out of tight spots, before!" Catherine brought up, though she didn't think about her choice in wording until after the fact, but still she brought up all the times David gotten out of trouble before, even during dire situations.
It wasn't the tone David wanted to use, but he felt it was needed, and he took an unheard tone of voice with Catherine, telling her sincerely that he had to consider the possibility of him being killed by the very same man who killed his father.
Seeing the shocked look in her eyes, David exhaled sharply as he began pacing around the TARDIS, his red and white vanes squeaking as he did, while he paced, Catherine recovers, a dejected look in her eyes as she's forced to consider the possibility.
"What about Jenny?" Catherine asks about her as she watched David deep in thoughts.
Stopping for a moment, David tells her that he spoke with the Ko'gan, they're going to watch over her if anything happens to him.
"And Mr. Pratchett?" Catherine asked about him.
Sighing, David tells her that if anything also happened to Pete, the Ko'gan will still watch over Jenny for them.
Either one surviving, they'll pick up the slack for the absence of the other.
They've worked out the arrangements when Hamon gave the word.
"What's going to happen to the TARDIS?" Catherine asked about it and there David gave her instructions what to do if he died, he wanted her to use it, keep up the good fight.
In between running adventures, he also wanted her to keep Jenny company when the Ko'gan couldn't.
He'll make sure the key gets to Catherine.
Dabbing her teary eyes, Catherine shook her head in disbelief as David resigned himself to his possible fate, but David wouldn't lie to her, even if she begged him.
At one point, she wanted nothing more than banish him to the dungeons, but here she was, a sobbing mess, afraid of losing her only friend since the betrayal at the hands of her own cousin.
"You kick his arse!" Catherine demanded David promise her, that even if he dies tomorrow, he'll give the Master a good arse kicking for everything he done.
Chain him to a boulder and knock it over the cliff side if he must, but make sure the Master gets his comeuppance.
A smile on David's face, he held out his hand as he shook Catherine's, thanking her for her services as his companion, and she thanked him for letting her come aboard, even if she forced her way through the door.
There's still nagging thoughts about the possibility of this failing, the Master escaping justice once, again, this time, all the men dead at his hands, and no one left to stop him, but they're just that, thoughts.
True his blasé nature wasn't something that won people over, but David showed his determination in bringing justice for his father's death.
Since everything happened and the word finally came, his notorious blasé nature took a serious turn, focused on efforts destroying the Master.
A starling changes in what he used to be when he obtained the TARDIS.
The conviction in his chocolate eyes, Catherine couldn't stifle the tears as she burst out crying, bear hugging David as she cried in his chest.
Even though the fiery Scottish princess made Judoon cry and bullied Sontaran into doing whatever she wanted, she couldn't help but cry.
Of course, she's quick to warn David not to tell a soul that the princess cried, which he promised, before she made him keep another promise.
If she ever marries, she wants David to walk her down the aisle, and if he so much as show up a second late, she promised him that he'll pay dearly for being tardy to her wedding.
"It's a deal!" David smiles as he pats the top of Catherine's head.
Seeing the time, he coxed Catherine to release him, telling her that he needed to head over to the Pratchett residence and speak with Jenny.
Slowly nodding, Catherine stepped to the side as she allowed David to walk towards the door, his head held high.
Sticking the photograph into his coat pocket, David exhales sharply, before uttering, "Allons-y!"
THE END