I Solemnly Swear I Am Up To No Good

Phrase that allows a person to see what is on the Marauder's Map. Told to Harry Potter by Fred and George Weasley

"When you want to open the map, say I solemnly swear I am up to no good; to close it, say mischief managed.

By Kally

“I solemnly swear I am up to no good”

By Carmel

Define I Solemnly Swear I Am Up To No Good Meaning