Talk:Lost and Found (Tangled)/@comment-4087607-20190407120912

Lord Dementias had three pupils in search of the Sundrop/Moonstone: Surgarby, Matthews and...(spoiler alert!) Mother Gothel!!

This explains everything! She knew about the Sundrop and Moonstone she's been in league with Zhan Tiri. This is why she kept Rapunzel in the tower, to keep the Sundrop hidden on her master's instructions.