"A thought that still haunts me," said Lupin heavily. "And there were near misses, many of them. We laughed about them afterwards. We were young, thoughtless -- carried away with our own cleverness." 

I sometimes felt guilty about betraying Dumbledore's trust, of course... he had admitted me to Hogwarts when no other headmaster would have done so, and he had no idea I was breaking the rules he had set down for my own and others' safety. He never knew I had led three fellow students into becoming Animagi illegally. But I always managed to forget my guilty feelings every time we sat down to plan our next month's adventure. And I haven't changed..." 

Lupin's face had hardened, and there was self-disgust in his voice. "All this year, I have been battling with myself, wondering whether I should tell Dumbledore that Sirius was an Animagus. But I didn't do it. Why? Because I was too cowardly. It would have meant admitting that I'd betrayed his trust while I was at school, admitting that I'd led others along with me... and Dumbledore's trust has meant everything to me. He let me into Hogwarts as a boy, and he gave me a job when I have been shunned all my adult life, unable to find paid work because of what I am. And so I convinced myself that Sirius was getting into the school using dark arts he learned from Voldemort, that being an Animagus had nothing to do with it... so, in a way, Snape's been right about me all along."

"Snapes not right about donkey shit," puffed out Amelia, with a wave of her hand.

 "Snape?" said Black harshly, taking his eyes off Scabbers; for the first time in minutes and looking up at Lupin. "What's Snape got to do with it?" 

"He's here, Sirius," said Lupin heavily. "He's teaching here as well." He looked up at Harry, Ron, and Hermione. 

"Not well," said Amelia.

"Professor Snape was at school with us. He fought very hard against my appointment to the Defense Against the Dark Arts job. He has been telling Dumbledore A year that I am not to be trusted. He has his reasons... you see, Sirius here played a trick on him which nearly killed him, a trick which involved me --"

 Black made a derisive noise.

Amelia scoffed in disbelief. "You didn't?"

"He did," sighed Lupin. Amelia scoffed again. "This is why women live longer."