The
story
is
set
in
a
world
where
supernatural
powers
exist
through
science,
and
magic
exists
through
religion.
In
the
story,
Tōma
Kamijō
is
an
ordinary
high
school
boy
with
terrible
academic
scores
and
a
power
called
Imagine
Breaker.
Imagine
Breaker
can
defeat
any
other
power,
but
it
also
undermines
Kamijō's
own
good
luck.
His
Imagine
Breaker's
immense
strength
is
literally
immeasurable,
so
hapless
Kamijō
is
listed
at
the
supernatural
level
of
0.
He
happens
to
meet
a
girl
in
white
hanging
off
his
window
balcony.
The
girl
says
she
is
being
chased
by
sorcerers,
and
Kamijō
learns
that
the
girl
is
a
Church
of
England
nun
whose
memories
have
been
forcibly
replaced
by
Index-Librorum-Prohibitorum
—
the
103,000
forbidden
texts
of
the
Church.