Norval Greenwood, a privileged musician who still lives with his mother in a Beverly Hills mansion, receives a letter from his estranged father asking him to come and visit him. Norval, who has not seen his father since he was five years old, makes the trek to a secluded cabin overlooking the coast in Oregon. His father, Brian, is initially welcoming to him, but soon begins to display aggressive tendencies and taunt and insult Norval, even threatening him with physical violence. All this comes to a head one afternoon when Brian attacks Norval with a meat cleaver, but in the ensuing struggle, Brian has a heart attack and immediately dies. Due to a lack of space at the local morgue, Norval is forced to keep his father's body in the cabin with him after having it embalmed. He attempts to stay in the house long enough for his mother to come and get him, but is repeatedly awakened by loud sounds from somewhere beneath the house. Finding a hidden family photo album, Norval sees a photo of his father and realizes that the dead man is not his father at all. He then finds a hidden hatch in the house leading to a bunker beneath, where he finds his real father bloodied and chained up. On his father's orders, he attempts to kill a man, Jethro, who arrives to torture his father, but Jethro escapes, promising revenge. After finally freeing Brian, Norval is forced to carry him upstairs into the house. Brian reveals to Norval that after he left him and his mother, he fled to Bangkok, where he and a group of three other men - Jethro, a large man named Dandy, and Gordon, who was pretending to be Norval's father - kidnapped the daughter of the richest man in Thailand and successfully held her for a large ransom. Brian fled the group with their shares of the money and has been on the runever since, funding Norval and his mother's expensive way of life with the money. Dandy arrives at the house and attempts to kill Norval, but Norval stabs him in the genitals multiple times with a barbecue fork, then suffocates him with plastic wrap before beating him to death with the rest of the roll. Norval helps Brian leave the house, but Jethro returns armed with a crossbow. Brian advises Norval to hide in Jethro's trunk and kill him when he least expects it; Norval obliges, riding along to a motel where Jethro has arranged a meeting with a prostitute. While Jethro and the prostitute are engaged in a BDSM session, Norval steals the motel keys and a check spindle, slashes Jethro's tires, then attempts to sneak into Jethro's room through an adjoining room. Upon spotting him, the prostitute holds Norval in a headlock while Jethro stabs him several times with the spindle, then leaves. The prostitute is horrified that she is an accessory to Norval's death, but Norval stirs and exits the motel, finding Jethro has crashed his car into a sign that has partially decapitated him. Jethro reveals to Norval that his mother was a prostitute who both Brian and Jethro slept with before Norval stabs him in the exposed part of his brain with the check spindle; Jethro exhales "Arthur!" before collapsing dead. Norval, wounded but alive, walks on foot back to the house where he left his father and lies down next to him on the lakeside. Norval apologizes to his father for never letting his mother get over him, and Brian weakly touches his son's hand.
On the review aggregator website Rotten Tomatoes, the film has an approval rating of 86%, based on 94 reviews, with an average rating of 6.89/10. The website's critics consensus reads, "Bloody horror with barbed wit, Come to Daddy anchors its brutal violence in a surprisingly mature approach to provocative themes". On Metacritic, the film has a weighted average score of 64 out of 100, based on 20 critics, indicating "generally favorable reviews".
