Complex sentence: Scrooge, Donald and the nephews Huey, Dewey and Louie are off to find the legendary Trojan Horse, unaware that the Beagle Boys are spying on them.
Split into simpler sentences: Scrooge, Donald and the nephews Huey, Dewey and Louie are off to find the legendary Trojan Horse. Little do they know that the Beagle Boys are spying on them.