Lupin and werewolf's

[Simon J. Branford]

No: HPFGUIDX 2705

Blaise wrote: "So the transformation cannot be triggered by moonlight, but
by the rising of the full moon.  And the moon was long since risen when
Remus transformed.  So there's a plot hole, and it's been driving me nuts!"

One possibility is that he transforms automatically on the night of the full
moon, no matter if he is inside or anything else is blocking out the
moonlight. If it is close to the full moon then being in moonlight triggers
the transformation.

The first point explains why he had to go to the shack, when he was a child,
in the first place. On the night of the full moon he would transform into 'a
monster'.
The night in the Shrieking Shack is then explained by it being an example of
the second of my points above. I am not sure, and have not checked, but I
believe that we are not told that the night in question is a full moon.

Simon