Echidna, the Mother of All Monsters, wants revenge on Hercules for killing several of her children, including the Hydra, the She-Demon, and the Stymphalian Bird. She makes an alliance with the mercenary Demetrius, who also wants Hercules dead. Demetrius rescues Hercules' mother Alcmene from a mugging, but it turns out to be a setup as the muggers were his men, in order to get Alcmene to trust him. Alcmene falls him love with him and they start dating. When Hercules and Iolaus find out about this, Hercules is uncomfortable about his mother having a new suitor, but she lectures him that she deserves happiness.
Eventually, Demetrius springs his trap, and magical archers devoted to Hera whom Echidna summoned attack the group and shoot Hercules in the gut with an arrow. Demetrius abducts Alcmene and takes her to Echidna's cave, then reveals that he never actually cared about her, with Alcmene calling him a real monster. Though weakened by the arrow, Hercules and Iolaus rush to the cave to rescue Alcmene. Thinking Hercules is dead, Echidna tells Alcmene she wanted to let her know how it felt when her children died and prepares to kill her. Hercules and Iolaus manage to defeat the archers and enter the cave just in time.
Hercules and Iolaus battle Echidna and Demetrius. Eventually, Echidna accidentally crushes Demetrius. Hercules uses the archers' arrows to pin Echidna's tentacles, immobilizing her. He draws a sword and prepares to kill her, but Alcmene, having sympathized with her due to them both being mothers, begs him to spare her life, pointing out they are not monsters. They leave the cave and Hercules collapses the entrance, trapping Echidna. Alcmene tells him, "Hercules, you make a mother proud."
Tropes
- Abandoned Area: It's revealed that Iolaus abandoned his old farm to resume Walking the Earth. He's honestly not even sure if the building is still standing, after all this time. He later sends Leukos there to hide out and meet up with Hercules, but Hera's Archers find out and get there first.
- Achilles' Heel: Cutting the bowstrings causes the Archers to evaporate.
- Armor-Piercing Response: While discussing Parent with New Paramour.Hercules: From where I stand, he is still a mystery.
Alcmene: I think I'm a mystery to you, too. - Arrow Catch:
- Defied during the ambush. The Archers pop out from multiple spots and fire all at once to prevent Hercules from doing this.
- Played straight when a surviving Archer takes a shot at Hercules before he goes into Echidna's cave.
- Berserk Button: Alcmene presses Echidna's when she accuses her children of being anything but innocent.
- Big "NO!": Alcmene after Hercules takes an arrow in the gut.
- Call-Back: The deaths of the Hydra, the She-Demon, and the Stymphalian Bird motivate Echidna.
- Continuity Nod: Hercules says he wasn't able to finish the wall around Alcmene's house, due to that business with Iphicles.
- Creepy Crows: One flies by right before Hercules and Iolaus come upon Leukos's dead body.
- Elite Mooks: Hera's Archers wield crossbows and arrows forged by Hephaestus. They agree to work for Echidna this time.
- Engineered Heroics: Demetrius tricks Alcmene into trusting him by rescuing her from a mugging he arranged.
- Even Evil Has Loved Ones: As demonstrated when Echidna talks about her dead children and lets out a sad wail.
- Eviler than Thou: Demetrius acknowledges this.Alcmene: You're a monster.
Demetrius: I am nothing compared to what you are about to see. - Eyes Never Lie: After the trick is revealed, Alcmene kicks herself over this, as Demetrius made a good show of pretending to be loving but always had stone cold eyes.
- Friendship Moment: During the trek, Hercules suggests Iolaus hang back because this is about his family.Iolaus: Wait. I do understand, but this is family for me, too. After all we've been through together, the risks we've taken together, you're like a brother to me. I don't know any other way to put it.
Hercules: The feeling's mutual. - He Knows Too Much: The Archers kill Leukos, the veteran that was attempting to warn Iolaus of what was coming.
- Hoist by His Own Petard: Echidna summons Hera's Archers to help in this plan. Hercules later uses the Archers' arrows to pin down Echidna.
- Hypocrite: Echidna denounces Alcmene for raising a killer and is immediately rebuked.Alcmene: Your children were monsters, just like you! They murdered and maimed for any god corrupt enough to use them!
- It's Personal: Echidna is out to kill Hercules and his mother as payback for what happened to her children.
- Laser-Guided Karma: Hercules agreed to help raise money for charity by taking on any challengers in athletic events. A belligerent man wants to do the hammer throw, as he feels Hercules needs to learn a lesson in humility. After his own rather successful turn, he tries to sabotage Hercules by revealing Alcmene's new relationship mid-swing, which causes the metal ball to go straight up. It quickly lands on the belligerent man's foot. Iolaus promptly returns it to Hercules, who then sends it flying off into the distance and thus wins the challenge officially.
- Monster Is a Mommy: Echidna, of course. She wants revenge against Hercules and privately mourns her children.
- Mugging the Monster: En route to see Alcmene, Hercules and Iolaus are confronted by a gang of bandits. Hercules doesn't have time for this and quickly smacks them aside, either into the nearby river or up in the trees.
- Nice Job Fixing It, Villain: After Hercules is downed by the arrow, the villains simply retreat rather than try to eliminate Iolaus, as well. He's able to save Herc's life and help at the cave.
- No One Could Survive That!: Hercules was considered good as dead after being hit by the Archer's arrow and his body was left behind. He barely survives due to being a half-god, but he's severely weakened.
- Noodle Incident:
- Hercules and Echidna are implied to have encountered each other at least once before. He and Iolaus are familiar with where her lair is, and she immediately recognizes Herc when he enters.
- Leukos says he fought in battles at Liguria, Chalcedon, and the Istrian Peninsula. In an apparent coincidence, the Battle of Liguria would later be cited as a major accomplishment of Meleager the Mighty.
- Demetrius briefly notes that Hercules and Iolaus have fought in a number of wars and would thus know a lot of soldiers across Greece.
- Not Quite Dead: Hercules is shot right before a commercial break and passes out. After a scene between Alcmene and Demetrius, we cut back to Iolaus trying to get Hercules to wake up. He succeeds and is able to help him along.Hercules: Oh, it's me all right.
Archer: Then you must die again.
Hercules: Can't you get it through your head? I didn't die the first time. - The Only One Allowed to Defeat You: Averted. The Archers expect Echidna to want to kill Hercules herself, but she is content to let them do it. Alcmene is the one she wants to kill herself for "raising a killer."
- O.O.C. Is Serious Business: Hercules typically prefers to avoid killing his opponents whenever possible, which is one reason why he rarely bothers with weapons. When Echidna is incapacitated by the arrows, though, Hercules picks up a sword and is fully prepared to slice her in half. Echidna going after Alcmene made him that angry, and it takes Alcmene to talk him down.
- Outliving One's Offspring: "The Hydra! The She-Demon! The Stymphalian Bird! All of them my children! All of them slain by Hercules!"
- Parent with New Paramour: Hercules grapples with his mother hooking up with a complete stranger. It goes sour in the worst possible way when Demitrius's true colors are revealed.
- Please Wake Up: Iolaus does this after Hercules is hit with the arrow. It works.
- Properly Paranoid: When approaching Iolaus, Leukos says he can't shake the feeling "the wrong eyes" are watching him and out to get him. He's absolutely right and ends up dead.
- Sealed Evil in a Can: In the end, Hercules seals off Echidna's cave, though he isn't sure how long it will actually hold.
- Seen It All: Iolaus warns Hercules that he heard someone is trying to kill him. Hercules quips that happens all the time.Hercules: I don't have the energy to be impressed.
- Skewed Priorities: Hercules expresses regret that he is more involved in helping strangers than looking out for his own mother.
- So Proud of You: Alcmene towards Hercules in the final scene.
- Sympathy for the Devil: After being made to think Hercules is dead, Alcmene ultimately sympathizes with Echidna's grief over her own children. It's part of why she asks Hercules to spare her.
- Tempting Fate: After fighting off Demetrius's men and causing him to flee, Iolaus says this wasn't that much fun.Hercules: I suppose you'd rather fight a monster.
Iolaus: Are there any left? - Unrelated in the Adaptation: Hercules killed the Nemean Lion at some point before the Underworld TV-Movie and, while not all the sources agree, it's typically considered to be one of Echidna's children. However, Echidna never mentions the Nemean Lion when discussing her dead children by name, so it had different parents in this continuity.
- Villain Team-Up: Demetrius proposes that he and Echidna join forces in order to eliminate Hercules.
- Worf Had the Flu: Due to the wound caused by the arrow, Hercules is weakened and has to hobble around, which makes it easier for Echidna during the final battle.
- Wrong Genre Savvy: After Demetrius's treachery is revealed, Alcmene assumes he's working for Hera and is told otherwise.Alcmene: But no one else hates Hercules and me as much as she does.
Demetrius: You're wrong. Echidna hates you even more.
