The episode begins with Cadpig telling the other Dalmatians that tomorrow is Valentine's Day, in her words: "A joyous celebration of the power and importance of love and friendship, and the ultimate guilt trip. The opportunity to give a valentine to someone who didn't give you one, and watch them squirm…[She] loves it!"
Spot comments that Cadpig sometimes scares her, which surprises Rolly as it's only "sometimes". They then notice Roger acting suspicious about the Dearly Farm, and while Cadpig suspects Roger has a wedgie, Lucky is perked by the mystery and they follow him to see what it is.
They follow Roger to his studio in the Dearly Farm house, but they are stuck behind the door to it. They do hear music and are concerned if he's taking up the trombone again (Spot claiming that the previous time it caused the chickens to mutiny). Anita then arrives and asks Roger if she can use the computer. Roger acts more suspicious, especially with a box under his shirt, but he claims he's working on a video game. Anita suspects he’s up to something, and Lucky claims they'll find out what it is.
At Villa De Vil, Cruella is eyeing her mailbox, seeing she hasn't gotten a single valentine. She tries to claim she is okay with this, but her anger on the mailbox claims otherwise before she wonders where Horace and Jasper are.
Horace and Jasper are in Cruella's kitchen baking a cake, but Cruella's entrance causes it to pop. While Cruella shows anger at this, Jasper claims it was Horace idea, since he wanted to bake a Valentine's Day cake. At first, Cruella acts pleasant and asks Horace who it's for (assuming it to be her), but when Horace claims he is hoping Nanny may like it, Cruella chases them from the kitchen, throwing the frosting to Horace, when he asks for it.
Cruella then makes a memo to wipe Valentine's Day from the calendar.
Back at the Dearly Farm, Roger is trying to hide what’s in the box, with Lucky, Cadpig, Rolly and Spot following him. Roger tries various cupboards in the Dearly Farm house, but this causes various items to fall on him. When he tries the hen house, he gets eggs pelted at him, and when he tries to hide it in the cow stalls, Duchess nearly sits on it, causing Roger to dive and get sat on instead.
He then tries to hide it in the tool shed, causing Cadpig, Rolly and Spot to run, not wanting to risk what's in the tool shed to fall on them.
Roger is soon able to find a place in the Dearly Farm barn, and Lucky checks what it is. It turns out to be a singing Valentine for Anita, from Roger. Lucky is disappointed in this, and when he tries to put it back, Dumpling then arrives, thinking it's a valentine for her, from Lucky. Lucky tries to get it back, but their struggle causes it to fling around the barn and collide with Scorch.
Lucky tells Dumpling that the valentine is for Anita from Roger, and then realizes Scorch taking it back to Villa De Vil. Lucky plans to get it back.
Roger is upset at how, when he actually remembers to make the valentine, he misplaces it, and Cadpig calls Lucky on this. Lucky tries to get Cadpig, Rolly and Spot to help, but Spot is concern, since Scorch is known to eat chickens, and Rolly comments what Cruella may do to them while Scorch may be eating Spot.
Lucky insists they won’t be doing it for him, but for Roger, Anita, their country, the flag and apple pie. Cadpig, however, sees it as they're doing it to cover Lucky’s tail, and Lucky claims he can work with that.
In Villa De Vil, Cruella considers sending herself flowers, but when she tries to send some anonymously, she refuses to give them her name, as it would spoil the surprise.
She then hears Roger's valentine and notices Scorch playing with it, and it has chocolates too. Cruella suspects that either the house is infested with large and romantic termites, or she has a secret admirer setting out to find who it can be.
With Horace and Jasper, Horace asks why he can't just give Nanny the cake and say, "Happy Valentine's Day," but Jasper points out that Nanny thinks they're criminals. Horace protests that they're "consultants on parole," but Jasper claims that if Horace wishes to get on Nanny's good side, he needs to creep up on her.
They notice Nanny riding up, on a bicycle, but when Horace stands in the road to greet her, a bump causes Nanny to have her vision obscure and she runs over Horace with the bicycle. Jasper suspects it time for Plan B.
At Stiffle Mall, Cruella has purchased a lot of valentine items and claims she can't wait to personalize them, when she finds who her secret admirer is.
Her first suspect is Starbuck, who shows terror at Cruella's presence and denies it being him. Cruella still thinks it to be him, but Captain Ahab (who is trying to keep Cruella at bay with a shark jaw) points out that Starbuck is only in love with himself. Cruella notices this too, but figures that her admirer can't hide forever.
At the Dearly Farm, Horace knocks on the door of the Dearly Farm house, but when Nanny answers it, she notices it is Horace and slams the door in his face. Jasper claims Nanny to be tough and has Horace try his own method.
In Villa De Vil, Lucky, Cadpig, Rolly and Spot are looking for Roger's valentine. Rolly is cautious on the plan, claiming Scorch isn't just going to give the valentine back. Spot then spots it, on a pedestal, and Cadpig wonders how they get it.
Cruella's second suspect is her business rival, Ralphie St. Lowrent. He claims that it wouldn't be ethical for him to like her, and while he may be a lot of things, he's not as dumb as he looks. Cruella then concurs as, "Anyone who wears such goes undergarments, doesn't have the taste to appreciate a prize like [her]."
Spot is able to fly up to the valentine, but as she tries to get it, Cruella returns and grabs the Dalmatians. She however hears the doorbell and thinks her secret admirer has come to her. She opens the door to see Roger, to her disappointment, and she gives him the Dalmatians back. Spot gets to Roger too, while being chased by Scorch.
Roger asks if Cruella has seen his valentine, and this causes Cruella to think Roger is her secret admirer, actually remembering Roger’s name.
Cruella brings Roger in to Villa Devil to admire her, and tell him how much the valentine means to her. She plays the song on it, claiming Roger has captured her through it, but Roger claims he wasn't thinking of Cruella. He hits the Valentine, which gets the song to continue, showing it to be for Anita.
Cruella is shock by the fact that Roger made a valentine for his wife, and kicks Roger from Villa Devil, not giving the Valentine back.
She then sets a Memo to erase Valentine from the face of the Earth, and begins to steal anything heart-related in Gruteley.
Back at the Dearly Farm, Captain is helping the Dalmatians make another valentine for Anita. Lucky has his doubts on it, but Cadpig claims Anita won’ notice the difference since she's human.
Rolly arrives and tells them about Cruella's heart theft. Cadpig takes pity on Cruella, claiming she needs TLC, love and help. Spot questions why Cadpig would want the Dalmatians to help Cruella, considering what she is like, but Cadpig comments that it is Valentine's Day.
Cruella is busy shredding the Hearts that she stole, and is about to shred Roger's valentine when she hears the Dalmatians coming as they bark.
She suspects they've come to gloat at the only person in the world, who doesn't get any valentine, but the Dalmatians are actually giving Valentine’s to Cruella, such as Lucky with a flower, Rolly with a gourmet chocolate bar and Cadpig with a Mood Ring (Cruella claiming she needs one, since her previous one exploded).
As more Dalmatians give her a valentine, Cruella is moved by this, and also sees that Scorch cares a lot about her, so she gives Roger's valentine to the Dalmatians.
Cadpig comments on the idea of giving someone a valentine just to make them happy, while Cruella heads off with Scorch to replace the items that she shredded.
Lucky gives Dumpling a valentine, and while it may not be as nice as Roger's one, Dumpling appreciates the thought, with Lucky cautioning her to not get mushy.
In the Dearly Farm house, Nanny hears some barking from outside, and when she checks on what it is, she sees Horace giving his valentine cake to the Dalmatians, since he didn't wish for it to go to waste. Nanny sees this and understands what Horace was trying to do, and invites him in for valentine tea.
Roger shows his valentine to Anita, and while she finds it beautiful, she hopes Cruella doesn't feel bitter on it.
Back at Villa De Vil, Cruella wishes Scorch a happy Valentine's Day.
- This is one of two episodes based on a certain holiday, the other being "A Christmas Cruella". Easter is mentioned in "Dalmatian Vacation", though, and jack-o'-lanterns are shown in "Love 'Em and Flea 'Em".
- This episode also reveals Horace's feelings for Nanny, which is also shown in "Home is Where the Bark Is" and "Frisky Business".
- The song that Roger has for Anita's valentine is to the tune of "This Old Man", just like another song set to the tune: "I Love You" from Barney & Friends.
- When Roger is trying to hide his valentine for Anita, he comments on working on a game called The Hunchbox of Notre Dame, a likely homage to the recent Disney film The Hunchback of Notre Dame, based on the Victor Hugo story.
- When Cruella thinks the valentine is from Starbuck, there is a life preserver ring behind them for a ship called the Titanig, a name likely similar to the RMS Titanic.
- When Cruella calls the florist store, she refers to it as: "Flowers R U", a likely homage to the Toys "R" Us store.
- In this episode, Cruella calls Roger by his actual name, instead of some other name beginning with an "R".
- When Cruella is stealing anything valentine-related, it is similar to the theft sequence in How the Grinch Stole Christmas.
- One of the heart-related objects she steals is a sign for "Hartz Car Wash"; this is a likely homage to Hertz Car Rental.
- Cadpig makes a sarcastic comment on how she feels when she suggests that 8-track tapes are a better idea than sneaking into Villa De Vil to get Roger's valentine.
- When Cruella is shredding the valentine items, she comments, "When you care enough to shred the very best..."; this is a likely homage to the Hallmark slogan: "When you care enough to send the very best..."
- When the Dalmatians have valentines to give to Cruella, Two-Tone's ears are white.
- When Cadpig comments on giving someone a valentine to make them happy, she exclaims, "What a concept!"; this is a possible homage to the Robin Williams album "Reality...What a Concept!".
- Lucky appears in the scene where Horace is giving his valentine cake to the Dalmatian pups, but when Nanny arrives, Lucky's ears turn white.
- While they deny it in this episode, Starbuck, Captain Ahab, and Ralphie St. Lowrent arrive in "Dalmatian Vacation", admitting they have feelings for Cruella.