Well, here's my idea:
"The Goonie! The Goonie!"
Mario, Luigi, Yoshi, Peach, & the Toads get lost in an ice cap after another daring rescue from Bowser. Out of nowhere, Blue Toad gets taken away by a Mother Goonie, due to her thinking he's her baby. Now it's up to Mario to save him, while fighting some icy foes and even Bowser.