It doesn’t happen often that an American colossus like Viacom sets its sights on an Italian animation studio — and then, rather than snapping it up outright, agrees to purchase just a minority stake.

The story follows Bloom and her friends Stella, Flora, Techna, Musa, Layla (Aisha), and is situated mainly in the Magical Dimension and on Earth. They call themselves "The Winx Club" and go on ...