This story is about Willump and Nunu, who search for the Heart of the Blue in the Freljord and make friends, and find out what happened to the yetis on the way.
Song of Nunu: A League of Legends Story contains examples of the following tropes:
- Actually Pretty Funny: Nunu and Willump set off a chain reaction that drops a rock on Volibear's head, knocking him out for a moment. As a personification of violent conflict, Volibear's reaction is a hearty laugh.
- Arc Words: "You cannot kill a story. You cannot kill a song." These words are the motto of the Notai people, representing their desire to create art to preserve themselves in the violence of the Freljord. The Notai hangings Nunu can find all have the lines as a stanza, and Nunu and his mother quote it. When Layka has to sacrifice herself to awaken the Heart of the Blue, she tells Nunu that she has become story and song, and can never truly die as long as Nunu remembers her.
- Bears Are Bad News: When Nunu blows the horn, it wakes up Volibear, who is cranky about being woken up and chases the duo. It's only by dropping some debris on his head that he calms down.
- Big Bad: Lissandra, the Ice Witch is this for the game, as she wants Willump's power.
- Bittersweet Ending: Nunu accepts the Heart of the Blue, and Lissandra realizes that there might be another path besides the endless, futile sacrifice she's resigned herself to. However, Nunu had to accept his mother's death and lost her spirit, and there are dark days ahead as the Watchers grow ever closer to Runeterra.
- Doomed Hometown: Ramshara, the ancient home of the yeti, now abandoned when all the yeti save Willump reverted to their primal instincts. Willump goes full Heroic BSoD on seeing it again, and even after Nunu snaps him out of it he's uncharacteristically solemn and sad through the whole section.
- Finishing Move: When an enemy is weakened it’s time for Nunu and Willump to finish them off with a variety of moves.
- It Was with You All Along: Willump gave the Heart of the Blue to Nunu the day they met. Willump couldn't tell him because Lissandra was spying on his dreams, so he let Nunu search for it in the hopes that Nunu would awaken it himself, which he did.
- Lore Codex: The Glossary has info on those that live in the Freljord, from characters, enemies, to even locations.
- Magical Flutist: With the magic of True Ice Willump added to fix his flute, Nunu can make something happen by playing a certain note, or notes.
- Mighty Roar:
- Willump often does this, as his roar can freeze a whole area.
- Volibear's roar rivals that of Willump's but louder and can summon lightning.
- Not So Above It All: Ornn might be the demigod version of a grumpy dad, but he sends Nunu on a quest for a special berry so he can have a treat and even shares a fistbump with him.
- Pet the Dog: While it took them dropping half a mountain on his head after he tried to kill them both, Volibear actually has a somewhat cordial conversation with Nunu and Willump.
- Savage Wolves: The Ice wolves of the Freljord aren’t exactly on friendly terms with the heroes, and now they've been corrupted by Dark Ice.
- Snowball Fight: Nunu and Willump love snowball fights, and they have them with each other, with Nunu kinda always winning.
- Songs in the Key of Lock: A number of the environmental puzzles and doors can be opened by playing the right notes on Nunu's flute.
- The Stinger: When Nunu heals Lissandra, (even though it doesn't last long) she can see for the first time in centuries, and sees that he not only has yeti magic, he is yeti magic, he is the Heart of the Blue. While it is unknown to her on how and why but it is true.
- A Storm Is Coming: Ornn, Volibear, and Lissandra all speak of a great war coming, which Nunu and Willump will play a vital part.
- Take a Third Option: Braum discusses this with Nunu, saying that most times when people try to make you choose between two bad things, there's a secret option number three. Through the story, Lissandra tries to talk Nunu around by claiming its either sacrifice Willump, or let the world die. But since Nunu has the Heart, there might be another option, and by the end Nunu, Willump, and Lissandra are all determined to find it.
- Ultimate Blacksmith: Ornn is one of the two demigods Nunu and Willump meet. At first he's not really fond of them (as he preferrs solitude) but he notices something in Nunu, a spark of Anivia, and he helps them make a cauldron for Braum.
- Ultimate Forge: Ornn's forge is located in a volcano that has rivers of lava as far as thee eye can see.
- When I Was Your Age...: Ornn complains that youngsters are too obsessed with magic and don't appreciate plain old craftsmanship like they used to, and makes Nunu and Willump work the forge so they know the value of hard work.
