The Birds have come back at the end of winter, ready for spring. They look in on Frog and Toad, still in hibernation in their respective beds and in their respective homes ("A Year with Frog and Toad"). While still asleep, Frog and Toad sing about their friendship and the new year ahead ("It's Spring"). Frog then wakes and decides to get his friend out of hibernation for the new year.

Once he's convinced that it's spring, Toad decides that he wants to plant a garden. Frog gives him some seeds. Toad plants them but is very impatient that they grow quickly. He sits up all night with his seeds, feeling bad because he's yelled at them and worrying that the seeds are afraid to grow ("Seeds"). He sings for them. He dances for them. He plays the tuba. By morning, they have begun to grow.

Now that it's morning, Toad knows mail should be delivered. He is sad, however, because he never receives mail. Frog goes home to write Toad a letter. He asks Snail to deliver it for him ("The Letter").

Frog and Toad go to the pond for a swim. Toad is uncomfortable that Frog will see him in his bathing suit. ("Getta Load of Toad"). Frog promises not to look until Toad is in the water. Toad asks Frog to instruct Turtle to leave so she won't see him come out of the water. Instead, Turtle calls mouse and lizard over to look at Toad. Freezing, Toad must eventually leave the water ("Underwater Ballet") and everyone gets a good look at Toad in his bathing suit.

Later, Toad brings lunch to Frog, but he is not home. He's left a note that he wants to be left alone on the island. Toad worries that Frog is sad. He rides a log out to the island and accidentally falls in the water, getting all of their sandwiches wet. It turns out that Toad is not sad; he is happy – he just wanted time alone to think about how happy he really is ("Alone"). Together, they eat wet sandwiches.

Meanwhile, snail is still on his way to deliver Frog's letter to Toad ("The Letter – Reprise").

Frog and Toad are at Toad's home, preparing dinner. They make cookies intended for desert but can't stop eating them ("Cookies").

Frog has a kite, which Toad tries to help him fly. ("The Kite"). The birds laugh at their failed attempts, but the kite finally flies.

It's now the end of summer ("A Year with Frog and Toad"), and leaves cover the ground. Both Frog and Toad plan a surprise by secretly raking the other's yard ("He'll Never Know"). They clean one another's yard but, as soon as they leave, the squirrels come and mess up their neat piles of leaves. Neither ever finds out the good deed each has done for the other.

Frog and Toad visit at home on a dark and stormy night. Frog thinks it's a good night for a scary story ("Shivers"). He tells the tale of a young frog – presumably himself – who escapes the clutches of a Large Terrible Frog before he is eaten.

Meanwhile, Snail is still on the way to deliver Frog's letter to Toad.

It's now winter. Frog and Toad are on top of a hill and prepared to sled down it, despite Toad's fear ("Down the Hill"). On the way down, Frog accidentally falls off the sled. Toad continues down the hill. He takes the wrong path – the dangerous and bumpy path. When Toad reaches the bottom of the hill, he is so mad at Frog for making him go sledding that he swears never to talk to Frog again. Snail arrives with Frog's letter to Toad. In the letter, Frog tells Toad how he can't be happy unless his friend, Toad, is happy. Toad decides to talk to Frog again. Snail, having delivered his first letter, is very proud ("I'm Coming out of My Shell").

It's now Christmas Eve. Toad is in his kitchen. He's terribly worried because Frog is late. He imagines all the terrible things that could have happened to Frog ("Toad to the Rescue"). Frog arrives. He's been wrapping Toad's present. Toad tells him how worried he's been ("Merry Almost Christmas").

Now back in hibernation, Frog and Toad are in their respective beds. It's almost spring again! The Birds sing ("Finale"), as Frog and Toad get ready for another fun-filled year.