I saw this in the featured story slot, and absolutely had to click it, because anything with Harry, time, and Sirius makes me want to read it (even if I haven't learned from the horrifying experiences of really bad stories). That gut feeling was really justified when I read this.
Though it was short, you, as a writer, got the emotions you wanted to portray through to us (the audience) so very well. The interactions between Harry and Sirius was really..intense? (forgive me as english is not my first language) And made me want to hug poor Harry.
And as siaru said, I do hope to see if you take it further with the two years that he has to live out due to the Time-Turner's imperfect operation requirements.