Prospero wants Miranda and Ferdinand to fall in love, but he does not tell Miranda that. When Miranda sees Ferdinand she immediately falls in love, as the only men she has ever seen before are her father and Caliban. Ferdinand also falls in love with Miranda instantly and promises to make her queen.
Prospero though, calls him a traitor and threatens to tie him up. Miranda fights for his freedom and Prospero agrees, if Ferdinand will do hard labor for him.