Emma, Henry and Mr. Gold search for Gold's son in New York; Hook, Cora and Regina look for one of Rumplestiltskin's most-precious possessions.
When a group of wedding guests in Massachusetts suffocate from the inside out, the team must find out how the toxin was delivered and targeted.
After a shift in violent animal behavior, the team tries to rescue Jamie and secure the leopard that may hold the key to curing the animal crisis.