When John Prince bribes a pharmaceutical magnate to cut off Sherwood's medical supplies, he threatens Tressie's delicate health and drives Robyn and The Hood to a daring heist.

When Chet Prince mistreats Alan's friend Elmore, Robyn and The Hood decide to crash his birthday party and steal from the richest playboy in town.

Lionheart Day kicks off with a surprise as John Prince offers to bargain with Tressie over Sherwood's future; while Tressie and Prince negotiate, Robyn starts to suspect things are not what they seem when Guy Gisbourne returns to crash the party.