In all his years of pranking, Sirius Black had never had a prank fail. He was after all, the King of Pranking. The Slytherin's hair had always turned pink right on schedule; Snivellus had always gone spinning up by his ankle; Hufflepuffs had always awoken to find their Common Room flooded on cue; Ravenclaws' books had always disappeared… In short, his pranks never failed.
It had seemed like the perfect plan- effective and humorous. He and James would get another laugh at the Death Eating gits. It would be perfect. One last hurrah to end their school days. Why not make Peter the secret keeper? No one would expect it. They would take Sirius in and question him- maybe torture and kill him, but in the end Sirius wouldn't be able to tell them where the Potters were hidden.
Only Peter would have that honor. And no one would ever suspect Peter.
While at school, meticulous planning had gone into every prank. Escape routes were noted, precautions were taken, prefect's rounds mapped out, the risks calculated and every possibility accounted for. It was the secret to their success.
Sirius Black was not one to slack when it came to pranking. Especially when the prank concerned the people he loved more than anything in the world. He had noted loopholes, possible incidents and he had accounted for every fluke conceivable.
At Hogwarts, Sirius knew he could trust the other boys implicitly. They would not fail him. They would carry out their designated tasks with unswerving loyalty and determination.
In the real world, it didn't work like that. As was natural, not living with each other anymore and not spending every waking second together had caused them to drift apart. If someone was missing, it was not as noticeable. And so, the Marauders' bond weakened without them noticing.
When he was at Hogwarts, Sirius could always count on a prank to cheer him up. As soon as the parchment and quill came out and Remus began diagramming the steps, Sirius couldn't stop smiling.
This prank was different. This was serious. It wasn't a joke- it was life or death. Sirius could barely smile when he thought of it.
The aftermath of a prank at Hogwarts always included triumphant hand slapping, uncontrollable laughter and more often than not, a detention. Or six. Receiving detentions didn't count as failure. Getting caught was insignificant. That didn't really matter.
Being imprisoned wasn't really that terrible. Well, it was completely awful, but sort of like detention in Sirius' mind. Yes it was worse and with no foreseeable end, but prison was to the real world as detention was to Hogwarts.
There was only one prank that had ever gone wrong and only one prank that had ever been so important. It was this prank that caused the collapse of Sirius' world. Sirius had made a mistake. A miscalculation. This time, Sirius Black made a critical error. He had trusted too much. He didn't account for a very important possibility. And that, that error made all the difference.
He had trusted Peter Pettigrew with the thing he loved most in the world.
And Peter Pettigrew should not have been trusted.