In Bayville High, Hank McCoy is teaching his chemistry class. Evan isn't
paying any attention, and Kurt tells him to listen, because it's
interesting. Hank explains to his students: "There are stable molecules,
such as water, and then there are your unstable molecules, like potassium
metal. Unstable molecules have weak atomic bonds and break up easily, kinda
like the defensive line on our football team." The kids laugh, except for
Evan, who sees his friends skateboarding outside. He asks to go to the
bathroom, and Hank tells him not to get lost – the best part is yet to come.
Hank makes an experiment with unstable molecules for the kids, and they're
very interested. He walks to close the blinds in the window, and sees Evan
outside with his friend. Evan notices him too. Hank closes the blinds and
gets back to the experiment, when suddenly he groans and holds himself in
pain. He hurries to leave the classroom, telling the kids he'll be right
back. In the bathroom, Hank washes his face. He falls in pain and then tears
off the sink in berserker rage, throwing it across the room.

Later, Principal Kelly is putting police tape on the ruined bathroom door.
Risty shows up and asks him who did it, and he says he doesn't know, but he
intends to find out. Risty says the place looks trashed – whoever must have
been very strong. "Or very angry", replies Kelly.

Kitty doesn't believe Kurt when he tells her McCoy did it – he's their
coolest and nicest teacher. Kurt insists that he's serious – McCoy was
losing it in chemistry, and nobody has seen him since. Kitty leaves to
class.

Evan and his friends are still skateboarding in the park, when suddenly Evan
hears Hank in a theatre. He finds Hank on a stage, looking angry and quoting
Shakespeare, and apologizes for skipping class. Hank is still acting weird,
but relaxes and apologizes for scaring Evan. Evan's friends call him, and he
asks McCoy if he'll be okay. Hank says he'll be fine, and Evan leaves.

Evan enters the Institute, bringing a package to Kitty in on the way. In the
Danger Room, the other X-Men are in the middle of a training session. Metal
spheres attack them, and Rogue gets hit. Nightcrawler, Jean and Shadowcat
get to where they're supposed to be, but Cyclops stays behind to help Rogue.
He doesn't make it in time, though, and Storm tells them that their time's
up. The scenario ends, and Storm congratulates them on the great teamwork.
The X-Men don't understand, saying that they failed – Spyke was supposed to
guard Rogue. Just then, Spyke enters and asks if he's late. The X-Men are
all angry at him, as because of him they failed and have to do it again
tomorrow. He apologizes as everyone leaves angrily. Before Storm leaves, she
tells Evan that nobody can count on him anymore.

Kitty enters the living room, and gets very happy at the sight of her
package. She hurries to open it, pulling out a weird-looking pyramid-shaped
hat. She models it to Scott and asks what he thinks, and he answers it's
very unique. She tells him it's supposed to stimulate brain power, and she
got it because of her geometry test - desperate times call for desperate
measures.

The following day at Bayville High, Evan comes across Hank McCoy. A little
scared, he promises he'll be in class today. Hank apologizes about what
happened at the amphitheatre - Evan caught him at a bad time - he likes to
go there to kinda get his head together - he gets a little entranced by the
whole Shakespeare thing. Evan says he understands, and Hank tells him that
he's a bright kid and he has a lot of potential – more than he knows. Hank
then shows Evan a picture in the trophy case of a younger him playing
football, and Evan asks in surprise if Hank played in Bayville. Hank says he
played three years – would have been four, but he just goofed off as a
freshman – it wasn't until he became part of a real team, that he truly
realized his potential. He advises Evan to pick his friends wisely – they
shape him in many ways. And about skipping class, he says, they'll forget
about it if Evan memorizes a little Shakespeare passage. Evan agrees.

Later in the gymnasium, Hank is coaching the girls, who are playing
roller-hockey. Jean is among the players, and Evan is watching. All of a
sudden, Hank grabs his head again in pain and anger. He turns around from
the girls, but just then one of them calls for him to catch her, as she
can't stop. He growls and catches her, and she looks terrified. Evan
approaches them and talks to Hank, and Hank snaps out of his state,
releasing the girl. She returns to the others and tells Jean that McCoy
looked really upset, but jean says she just surprised him, that's all. Evan
asks Hank if he's feeling alright, and Hank answers that he's fine – he's
just a little jumpy. Evan and Jean look at each other, worried.

That night in the Institute, Evan is trying to memorize the Shakespeare
passage that Hank gave him, but can't get it. Kitty offers him to try the
brain-power stimulating pyramid hat, but he doesn't believe it really works.
She says that if she can walk through walls and he can shoot boney spikes,
then anything's possible. He still isn't sure, but she says that after
blowing off the Danger Room session today, his brain could use some
recharging. He agrees and puts it on, when the doorbell rings. He goes to
the hall to see who it is, and finds Hank McCoy talking to Jean by the door,
asking to see Professor Xavier.

In Xavier's study, Hank tells Xavier that he should've listened when Xavier
reached out to him when he was young. He realizes now he can't control it
anymore – not by himself – he needs Xavier's help. Xavier asks McCoy what
he's been feeling, and Hank answers that it's like he's got an animal inside
of him – a beast – and it's tearing him to pieces. Charles asks how Hank
manages to suppress it all those years, and Hank explains it was through a
serum he created, but it's not working anymore – he needs help before
somebody gets hurt. Xavier tells Hank to take a seat and starts reading his
mind. In Hank's mind, Xavier sees a blue-furred beast. He stops reading
Hank's mind and tells him he can't help him. Hank is upset, saying that he's
too dangerous to be trusted, and Xavier agrees, saying that Hank needs to
make certain sacrifices until he gets this under control. Hank says that
teaching is his life – he's nothing without it – and Xavier says that this
mutation is a natural part of him – the only way to suppress it is with his
own strength of will. Hank says he tried, but Xavier says Hank stopped
trying when he started depending on the serum – he has to reach from within
– it's the only way. In despair, Hank says he's worn out – he can't fight it
anymore.

In Bayville High, Hank is alone in his lab, trying to create a better serum.
After some work, he drinks a serum, and screams in pain. Kelly hears him
from his office and rushes to the lab. Hank knocks over things
uncontrollably, grows blue fur and fangs and turns into a beast. Kelly
reaches the lab and finds total chaos, when suddenly Beast attacks him, and
Kelly runs in terror. The exit doors are locked, so he gets into a room and
leans on the door to keep it close. Beast tries to get in, but leaves when
Kelly pulls the fire alarm. Kelly exits the room to find the exit doors
smashed and Beast's lab coat on the floor, with the name tag "McCoy".

In the Danger Room, the X-Men are watching a television news report, saying
that a state of emergency has been declared throughout the city as reports
of a wild beast continue to flood in. A reporter interviews Kelly, and Kelly
says that he's seen the beast with his own eyes and he knows who it is -
it's Hank McCoy, a chemistry teacher at Bayville High – he's gone mad.
Wolverine says that based on sightings and the wake of damage, it's clear
he's headed north. Xavier agrees and sends the X-Men to get him, reminding
them they don't want to hurt him.

In the scrap yard, Kitty and Jean locate Hank. Shadowcat chases him, phasing
through obstacles, as Jean tells Wolverine they found him. Beast manages to
surprise Shadowcat but she phases through him. He tries attacking again, but
Jean throws a car at him. Wolverine and Spyke get there and Wolverine
battles Beast, but Beast has the upper hand. Eventually Hank runs away, and
Logan takes off after him. Jean tells Ororo through the communicator that
Beast is still heading north, and Storm replies that they'll be waiting.
Shadowcat wonders where Beast is heading, and suddenly Spyke realizes he's
going to get his head together. He starts running, and Jean and Kitty
follow.

In another part of the city, Storm, Nightcrawler and Rogue spot Beast in an
alley. He manages to disappear and then surprises them from a roof, but
Ororo sends him back up. Kurt teleports up, but can't find Hank. He looks
over the edge, and finds Beast on the wall. Beast jumps at him, and they
fall through the roof. Nightcrawler teleports to avoid the fall, and by the
time he appears again Beast is gone. Rogue and Storm enter, and Beast
surprised them again. Cyclops shows up and blasts Beast through a wall.
Storm uses her communicator to tell the others he's on the move again.

In the amphitheatre, Spyke finds Beast. He tries to get through to him,
saying that it isn't him, and that he has to fight it. Beast doesn't seem to
listen, and Wolverine attacks him as Spyke uses him communicator to tell the
others where they are. Wolverine and Beast are having a fierce battle, but
Beast is winning again. Jean saves Logan, though, as she throws Hank and
holds him telekinetically. It starts raining, and Evan decides to try a
different approach – he walks to Hank and starts quoting the passage Hank
gave him at school. His aunt shows up with Scott and tells him to stay away,
but he doesn't listen, and just keeps quoting. Kurt teleports Xavier in and
Xavier reaches to Hank telepathically, telling him to take control and not
give up – he's stronger than the beast.

In the Institute, the X-Men are having breakfast, as a news report says that
after a night of terror, local teacher Hank McCoy's whereabouts remain
unknown, but until he's found, police have vowed to continue their search.

In another room, Hank complains to Xavier and Evan that he still looks like
a monster. Xavier tells him that now he's in the one place where that
doesn't matter. Hank says that he can still feel the beast inside, and
Xavier tells him that he probably always will. Hank says that the worst part
is the very thing he feared most has happened - his teaching days are over
now that he looks like this - but Evan tells him the professor can make him
an image-inducer. Hank declines, saying that Hank McCoy is a wanted
fugitive, but Evan says he can look like anyone he wants. Hank still
declines, as he can't risk teaching when there's a beast inside of him
trying to claw its way out. Xavier tells Hank that what he needs are
students who know his secrets, who have secrets of their own, and who need a
man of his compassion to teach them.

In the kitchen, Scott finds Kitty's hat in the trash can. He asks her if she
failed the quiz, but she says she aced it. He asks what changed her mind,
and she says she looked in the mirror and found that it looks hideous –
she'd rather study than ruin a good hair day. Xavier and Evan enter, and
Xavier introduces the X-Men to their newest faculty member. Jean welcomes
Mr. McCoy, but he tells her to just call him Beast.