Waking up one Sunday morning, Tenchi is pleasantly surprised to look outside and see that it has begun snowing. Sasami and Ryo-Ohki are already outside enjoying themselves, and as Tenchi watches them marvel at the falling snow, he recalls how, as a little boy, he once ran outside and did exactly the same thing.
Not everyone is a fan of the cold weather, however; huddling up by the kotatsu, Ryoko wants nothing more than for Tenchi to switch off the snow and restore the good weather! Unfortunately for her, Earth isn’t quite up to the level of weather manipulation- not only is Tenchi unable to switch off the snow, he even has to go out in it to bring Katsuhito back to the main house for breakfast.
Making his way up to the shrine, Tenchi enters Katsuhito’s house to tell him that breakfast is ready. When it looks like Katushito is still fast asleep under his blankets, Tenchi tries to shake him awake, only to discover that the only thing under the covers is a handful of rolled-up blankets. Katsuhito laid them there as a decoy, enabling him to launch a surprise on Tenchi with his wooden sword. Dodging, Tenchi eventually manages to disarm Katsuhito, who promptly retaliates by drawing a wooden knife- an important lesson to remember is that an enemy may have more than one weapon.
Whilst Sasami has fun turning Azaka and Kamidake into giant snowmen, both Nobuyuki and Tenchi find that they have more serious tasks to attend to. Poor Nobuyuki is so busy that he even has to go into work on a Sunday, whilst Tenchi has to attend a sword fighting lesson with Katushito. As part of his training, Tenchi has to keep a block of wood in the air by hitting it with his wooden sword whilst balancing on a field of wooden pegs. Tenchi seems to be doing quite well, so Katsuhito decides to liven things up a bit by throwing a few rocks at him. Tenchi easily deflects the rocks with his wooden sword, but even as he congratulates himself on his success he is finally knocked down when a pile of snow slides off a branch and buries him.
As Tenchi and Katsuhito move onto sword fighting, Ayeka comes out to bring Tenchi a hot drink. Watching them fight, she realises that their style is reminiscent of the sword techniques used on Jurai, but before she can think about it further, Katsuhito stops the lesson and leaves Tenchi and Ayeka alone to enjoy the drink by themselves. As they sit together, Tenchi explains to Ayeka that Katsuhito’s sword training has been a part of his life for years- he has never even stopped to consider why he does it.
Before they can talk any further, Tenchi and Ayeka are interrupted by Sasami, who has spotted something interesting whilst skating on the lake. Taking them down to the lake, Sasami shows Ayeka and Tenchi what she discovered- a small sapling has sprouted up from the middle of the lake. Judging from the energy strands it keeps giving off, this sapling must be a part of Ryu-oh- somehow, Ayeka’s spaceship has managed to begin regenerating itself.
After dinner, Nobuyuki and Katsuhito decide to enjoy a few bowls of sake together, and Ayeka and Ryoko are quite to happy to join them (and consume more than their fair share of the drink). Not wanting to join in, Tenchi has to watch as his friends and family get steadily drunker. Worse yet, when the others run out of drink, they send poor Tenchi to buy some more.
Whilst waiting for Tenchi to get back, Ryoko and Ayeka soon fall asleep, and Nobuyuki takes the opportunity to break out a bottle of the good stuff from his secret sake stash. As he and Katsuhito share the bottle, they go outside to look at the snow. The snow evokes a particular memory for them, and once, they hated it because of that, but now, both seem to be at peace with those memories.
Eventually returning to the house with the sake, Tenchi only wants to hand the drink over to his father and grandfather, but even as Sasami greets him in the hall, he suddenly collapses. The cold weather and all of his hard work have taken their toll on Tenchi, and now he has come down with a fever.
All of the adults have fallen asleep, so Sasami runs outside to consult with Azaka and Kamidake on Tenchi’s condition. The two guardians conclude that he has the flu, and suggest that some sap from Ryu-oh might be able to cure it. Obeying their advice, Sasami goes out to the lake and prays to Ryu-oh to help her. In response, the little sapling exudes a single drop of sap for her to take back to Tenchi.
Asleep in bed, Tenchi finds his dream filled with past memories, of another snowy day from long ago. Little Tenchi was happily building a snowman when Nobuyuki came home to give him some terrible news- his mother was dead.
Thanks to Sasami’s efforts, Tenchi is feeling much better by the next morning. The young princess was watching over him all night, eventually falling asleep by his bed. After thanking her, Tenchi covers Sasami with a blanket before running outside- his dream memories have reminded him of something important.
Rushing up the steps that lead to the shrine and then beyond, Tenchi finally reaches the top of the hill- his mother died on a snowy day like this one, so what better time to commemorate that day by visiting her grave? At the grave, Nobuyuki and Katsuhito are waiting for him, and the trio take a moment to pray before updating Tenchi’s mother on how her son is doing- he may need more practice with swordplay, but he certainly seems to have been successful with the girls lately.
As Nobuyuki and Katsuhito leave, Tenchi stays a moment longer- at least until Sasami comes to reprimand him for getting up so soon after being ill. Azaka and Kamidake weren’t even sure that the sap would work on Earthlings, but in Tenchi’s case it seems to have been a success. Tenchi is feeling much better- at peace with the memories of the past, and ready to face whatever the future holds.