The Sinner Season 4 Ending Explained: What’s Happening on Hanover Island? Why Was Percy Depressed?

The Sinner Season 4 concludes a thriller anthological series that began in 2017 starring detective Harry Ambrose, masterfully played by Bill Pullman. As we saw in our review of The Sinner Season 4, in this final chapter the detective, now retired for more than a year, goes on vacation with his partner Sonya on Hanover Island. Here, during a sleepless night, Harry will witness the suicide of a local girl, Percy; but things are more complicated than they seem, and the investigation of the former policeman will bring to light the sordid secrets of the inhabitants of the island. If you have concluded this series created by Derek Simonds, you will know what we are talking about; but perhaps there are still several doubts that nag you and to which you would like to find an answer. So, let’s try to do it together in our explanation of the ending of The Sinner Season 4.

The Sinner Season 4 Ending Explained: What’s Happening on Hanover Island?

Already from Part VI and VII of The Sinner Season 4, we begin to understand that Percy’s death, in reality, represents only the tip of the iceberg and that something much bigger is happening on Hanover Island. The murder of Brandon Keyser begins to bring out a sordid truth that involves many of the local inhabitants: there is an illegal traffic of illegal immigrants who are transported with fishing boats and for whom false documents are made to be able to cross the border with Canada. One of these irregular immigrants was precisely the South American woman whom, in a flashback, we had seen wounded and frightened together with the deceased Brandon; a woman of whom, unfortunately, all traces will be lost.

In the penultimate episode, again through a flashback, we discover that Percy had become aware of this human trafficking and that she had decided to file a complaint by going to the police station, just a few hours before her suicide. Here she had found the policeman Josh Moore who, after listening to the girl, pretends to call the boss Lou Raskin and escort Percy to him. In reality, Josh, who thus proves to be corrupt, leads the girl to her uncle and her father, Colin and Sean Muldoon. This makes us understand that the two men are also involved in the racket of the island.

How Does The Sinner Season 4 End?

In the eighth and final episode of The Sinner Season 4, we watch Detective Ambrose try to find a link between the illegal trafficking of illegal immigrants and Percy’s death. After returning to the shipyard, where he finds the boat that was used for the transport of illegal immigrants – the “Valerie” – completely burned, the man goes to the house of Don, owner of the shipyard, to ask him a few questions. Don not only tells him nothing but calls the police station to have him arrested for trespassing. Instead of transporting him to the station, however, the police chief Lou Raskin confesses to him that the results of the ballistics tests confirmed that it was Verne Novak, the man in charge of the racket on the island, who killed Brandon Keyser, as the latter, however, he no longer wanted to be part of the criminal organization.

At this point, Lou and Harry decide to continue investigating together, because the retired detective is convinced that Percy committed suicide due to feelings of guilt for someone’s death (in the fifth episode we had seen Emiliana, guardian of the pier, confess to Harry that the young woman felt guilty about it). The two thus discover that, two years earlier, the Lam family, formerly employed by the Muldoons, had suddenly earned a lot of money and had purchased a fishing license. Not only that: the Muldoons had also given the Lam an island, Crescent Island, for a truly negligible amount. Too many suspicious events to represent a simple coincidence. Going to Crescent Island Harry discovers the grave of Bo, the Lam’s favorite son who, according to the family, was in Hong Kong.

Why Was Percy Depressed?

Not surprisingly, the depression that had struck Percy had begun just two years before his suicide. Determined to find out more, Harry goes to the Muldoon house, where he finds Sean. On this occasion, Percy’s father, wracked with guilt for the truth so long hidden, reveals that Bo is not in Hong Kong, but died at their hands. Through a flashback we thus discover that, just two years earlier, the Muldoons discovered the missing loads of fish, starting to suspect that Bo, at the time employed by them, had stolen them from them and then sold them under the counter.

Sean, Colin and Percy decide to go out on a boat with Bo at night in an attempt to get him to confess. Thus, an argument begins in the open sea – in which Bo declares himself innocent – which leads to a terrible scuffle between Sean and Lam’s son; to stop them, Percy takes the gun and shoots Bo who is killed instantly. The three then decide to go, together with the matriarch Meg, to the Lams’ house to return the body and come to terms with them: in fact, they buy their silence with a fishing license and the sale of Crescent Island. But Percy will always feel guilty for killing an innocent boy.

Did Percy Really Commit Suicide?

The night Harry saw Percy throw himself off the cliff, he was not mistaken Percy did indeed commit suicide, due to his depression resulting from feelings of guilt over killing the Lams’ son. A few minutes from the end of the last episode, we return to the initial flashback, in which Percy is escorted by the policeman Josh to his uncle and her father. The two then take her to the family home, where Meg is also staying, and here the girl has an emotional breakdown: she realizes that her family is rotten and full of secrets and is convinced that she is the main cause of their ruin. Now in despair, Percy leaves the house, to meet his death. So let’s go back to the present: Harry goes to the exact spot on the cliff where Percy committed suicide and has one last imaginary conversation with her.

Who Was with Percy On The Headland The Night Of His Suicide?

One last doubt remains to be resolved: who was the mysterious figure with whom Percy argued during the night of his suicide and to whom he gave one last look before jumping off the cliff? It was Bo, or at least, the boy’s memory, who continued to haunt her until the day he died. We understand, therefore, that for the girl, suicide represented the only solution to get out of the suffering that she had been carrying behind her for too long.

How Detective Harry Ambrose Dies?

Continuing his imaginary conversation with Percy, Harry tells her he understands how it feels to be wracked with guilt and just wants to leave it all behind to feel some relief. We know Harry’s sense of guilt derives primarily from the death of Jamie Burns (third season of The Sinner) and, secondly, also from realizing how, to obtain justice, he always has to pay too high a price, in this case, the ruin of the Muldoon family. Percy, finally, asks him if now he can see another solution to get out of all this suffering. Harry doesn’t answer and we leave him there, on that cliff, unaware of what will be his fate. Will he decide to commit suicide too, as a last resort, or will he grit his teeth and carry on, if only because of the love he feels for his partner Sonya? We also believe in the second option because, in the last minutes of the final episode, we see how, in reality, Harry’s actions have brought peace to the hearts of the island’s inhabitants. And perhaps, we hope, also in him.