He's just 'building castles in the air' if he thinks he can open a restaurant without any money.
Millionaires built their 'castles' along the lake.
(..) Dialogue: Marked=..,Default,NTP,!Effect,Yes, Hermione. Dialogue: Marked=..,Default,NTP,!Effect,l think this is gonna be\Nexactly like wizard's chess. Dialogue: Marked=..,Default,NTP,!Effect,Castle to e! Dialogue: Marked=..,Default,NTP,!Effect,Pawn to c! (..)2001 Harry Potter and the Sorcerer's Stone
(..) Dialogue: Marked=..,Default,NTP,!Effect,Alright. Harry, you take\Nthe empty bishop's square. Dialogue: Marked=..,Default,NTP,!Effect,Hermione, you'll be\Nthe queen-side castle. Dialogue: Marked=..,Default,NTP,!Effect,As for me, l'll be a knight. Dialogue: Marked=..,Default,NTP,!Effect,And then... (..)2001 Harry Potter and the Sorcerer's Stone