Arcane Power focuses on the arcane heroes: characters who wield spells. The supplement includes new builds for wizard, warlock, sorcerer, bard, and swordmage classes. There are new spells and paths for character to follow such as Cosmic and Storm Magic for Sorcerers, a new pact for warlocks and the new paragon of Arcane Hunter as examples.

"Grizzly place, this is," The knight murmured to himself. "And I cannot say I condone this, hanging these people like decoration. If I were in charge, I tell you, things would be different. Much different." The knight had come to cut down the bodies. He stopped for a brief moment to look over each of them. The ghastly expressions etched upon their dispatched faces. The rain and win beat against the knight, and the bodies swayed a bit.

A lone figure sits on the rocky side of a small hill overlooking a wooded valley. It is the middle of the night, that darkest hour when spirits are said to be about; the full moon gives only feeble, murky illumination though heavy clouds.

Looking up, he wonders, perhaps for the first time, "Who am I? How did I get here?" His clothing registers a battle; he is dwarven, of the hill clans. Nothing more is forthcoming.

Five heroes at a tavern met,
treasure to find and blood to let.
A human knight, an elven mage,
a dwarf who didn't know his age -
two others joined them in this fight
for honor, duty and what was right.

Off they went to save fair maiden,
with swords and spells and packs all laden.
The hobbit was a ranger born,
who led them through thistle and thorn.
He brought them to the tower, where
the dragon stashed the maiden fair.

The doors were locked, no key in sight -
it seemed to be a dreadful plight.
But our gnomish thief did save the day;
he picked the lock to open the way.

Dark alley, day one:
Fatal wound spurts red. Quest failed.
Never hire a thief.