请调整浏览器窗口大小或者请使用手机查看!
Tia unleashes a deadly attack on Bristol Cove. Ryn, Ben and Maddie race against time to find a cure for Xander's mysterious illness, while anticipating Tia's next move. Baby Hope returns to land to reconnect with Ryn.
Ryn, Ben and Maddie must protect Bristol Cove from Tia's army. Meanwhile, Ben's injections are producing unexpected results, which alarms both him and the others. Xander juggles best man duties at Calvin's wedding while also helping Helen.
In an effort to save Hope, Ryn and Ben confront Tia in an undersea battle between the mermaid tribes. Maddie and Robb work to find a cure for Xander, while Helen and the hybrids help restore order. Ted struggles to accept Ben's reality.
Ben's shocking decision to let the reporter die at the end of season two has ripple effects in his relationship with Maddie and Ryn. Meanwhile, a dangerous, sophisticated new mermaid arrives in Bristol Cove, challenging Ryn's leadership and igniting an epic undersea battle between rival tribes. All of this is complicated by the fact that Ryn's baby, now being carried by a surrogate, must be protected at all costs.