Back in [Gryffindor Tower], [Harry] realizes the urgency of stopping [Voldemort] and explains the situation to [Ron] and [Hermione]. He then goes to bed, unexpectedly finding his [Invisibility Cloak] back in his bed.
Detention in the Forbidden Forest
[Filch] takes [Harry], [Hermione], [Neville], and [Malfoy] down to [Hagrid's hut] to serve their [detentions] in the [Forbidden Forest], lecturing them as they go.
[Hagrid] leads [Harry], [Hermione], [Neville], and [Malfoy] to search for the killer of a [unicorn] in the [Forbidden Forest]. He splits them into groups and sends [Neville] and [Malfoy] off with [Fang].
Walking through the [Forbidden Forest] in search of a [unicorn], [Harry], [Hermione], and [Hagrid] encounter the [centaurs] [Ronan] and [Bane], who are rather unhelpful.
As [Hagrid], [Harry] and [Hermione] leave the [centaurs], [Hagrid] spots [wand sparks] from [Draco] and [Neville] and runs off after them, leaving [Harry] and [Hermione] concerned behind him.
[Hagrid] returns upset with [Malfoy] and [Neville], and sends [Harry] off with [Malfoy] and [Fang] instead.
[Harry] and [Malfoy] find the dead [unicorn], and see something drinking its blood that makes Harry's [scar] burn. [Malfoy] runs and a [centaur] shows up to chase off the mysterious cloaked figure.
[Firenze] invites [Harry] to ride him to safety, infuriating [Bane]. He takes him to [Hagrid], however, explaining [unicorns] and [unicorn blood] - and [Voldemort]'s desire for the [Philospher's Stone] - to [Harry] along the way.
Chapter 16 - "Through the Trapdoor" - In which the students begin their exams, Hagrid lets slip how to control Fluffy, HRH try to warn Dumbledore but he has been summoned away. Fearful that Snape is about to make his move to get the Philosopher's Stone, HRH decide to go after it themselves. Under Harry's invisibility cloak they make their way to Fluffy, put him to sleep, and go through the trapdoor, past plants, chessmen, and potions.
Exams and Other Worries
The first years get through their exams, and though [Harry] still thinks constantly about [Voldemort], [Ron] and [Hermione] grow less worried over time.