Upon arrival at the Trapp family home,
Maria learns that she is the twelfth in a long line of governesses who have come to look after the children since their mother died.
In fact, her predecessor lasted only two hours.
Her impulsive comments, untidy dress and undisciplined manner leave the captain skeptical that she will fare any better, but he whistles for his children and,
standing at attention, they introduce themselves... formally, at first; less formally later:

Liesl, 16 and without need of a governess;
Friedrich, 14 and impossible; Louisa, 13 and an experienced prankster; Kurt, 11 and incorrigible; Brigitta, 10 and an observant fashion critic;
Marta, 7 and a fan of pink parasols;
Gretl, 5 and always last
(because she is the most important).

Introducing the von Trapp children:
Just as Maria begins to feel sorry for the
"poor little dears," she discovers the precious gift they left in her pocket and her apprehensions
about them are confirmed.

At dinner, later that evening, Maria sits down to dinner with the family, where after a short blessing, the new governess soon has her young charges bawling with pangs of guilt that their father prefers to diagnose as indigestion and Maria dismisses as happiness.

Although the captain (Christopher Plummer) is first introduced laying down the law to Maria and whistling for his children like animals, it is at the dinner table that the man behind the military demeanor first begins to peek through.

He is more preoccupied than uncaring,
if deliberately so, and although he appears not to notice when Liesl stealthily departs the dinner table for a rendezvous with Rolfe, the delivery boy.

She later learns he was paying more attention than she thought. Rolf and Liesl sing and dance.
Liesl (Charmian Carr) and Rolfe (Daniel Truhitte), "sixteen going on seventeen" and
"seventeen going on eighteen,"
are only able to meet when Rolfe comes by to deliver telegrams.

He has considered sending Liesl a telegram himself,
 just so he could deliver it.

"Dear Liesl, I'd like to be able to tell you how I feel about you. STOP.
Unfortunately,
this wire is already too expensive.
Sincerely, Rolfe."

After an admonition to Liesl that the captain should
avoid seeming "too Austrian" in the current political climate, Rolfe confesses that she is really the one he worries about:

You are "sixteen going on seventeen." Baby, it's time to think. Better beware. Be canny and careful. Baby, you're on the brink.

"You are "sixteen going on seventeen." Fellows will fall in line. Eager young lads and rou鳠and cads will offer you food and wine. Totally unprepared are you to face a world of men.

Timid and shy and scared are you of things beyond your ken. You need someone older and wiser telling you what to do. I am "seventeen going on eighteen." I'll take care of you."
 

"I told you today I didn't need a governess.
Well, maybe I do." --Liesl.

Liesl is soon joined in Maria's room by her siblings who arrive seeking reassurance during the thunderstorm, or ostensibly,
to check on Maria and make sure she isn't scared.
After a trying first day,
the children and their new governess finally
bond over a rousing rendition of

"My Favorite Things":

Raindrops on roses and whiskers on kittens.
Bright copper kettles and warm woolen mittens.
Brown paper packages tied up with strings.
These are a few of my favorite things.

Cream colored ponies and crisp apple strudel.
Door bells and sleigh bells and schnitzel with noodles.
Wild geese that fly with the moon on their wings.
These are a few of my favorite things. Girls in white dresses with blue satin sashes. Snowflakes that stay on my nose and eyelashes. Silver white winters that melt into springs. These are a few of my favorite things. When the dog bites, when the bee stings, when I'm feeling sad, I simply remember my favorite things,
 and then I don't feel so bad.

Despite having been warned that "The Von Trapp children don't play; they march," when the captain leaves for Vienna to visit the baroness, Maria and the children break all the rules.

Decked out in play clothes made from the drapes that used to hang in her bedroom, they go on a picnic where Maria teaches the children how to sing:

"DO, a deer, a female deer.
RE, a drop of golden sun.
ME, a name I call myself.
FA, a long, long way to run.
SO, a needle pulling thread.
LA, a note to follow so.
TI, a drink with jam and bread.
That will bring us back to DO."

Although a simple song, "Do, a Deer" provides the musical foundation for one of the film's greatest improvements over the stage production...
an extended montage that not only allows the audience to watch the bond between Maria and the children develop through music over a period of time,
but also permits the children to
"learn how to sing" over time rather than in a single sitting as happens in the stage show.
Aside from its expository function however, the montage also gives the audience a better sense of the story's setting through its panorama of real Austrian locales, in Salzburg and beyond.

So, Do, La, Fa, Mi, Do, Re. So, Do, La, Ti, Do, Re, Do.

Do-Mi-Mi, Mi-So-So, Re-Fa-Fa, La-Ti-Ti!

When you know the notes to sing, you can sing most anything!"

The baroness meets Georg's wet children The captain is far from amused when he arrives home to find his children and their governess soaked to the skin, having tumbled out of a canoe into the lake in their excitement to see him.

Angered at her outspokenness, Captain von Trapp dismisses Maria and orders her to return to the abbey. In the silence that follows this pronouncement, the captain hears music coming from the house and goes inside to investigate.

The captain and his children reconnect. Astounded to discover his children singing "The Sound of Music" for the baroness, the captain is moved to join them, and over the course of the song, the estranged family reconnects through the music.

Armed with a better understanding of the captain and his intentions toward the baroness, Maria continues on with the family, redefining her governess role to include the task of preparing the children for a new mother.

"High on a hill lived a lonely goatherd. Lay-ee ode lay-ee ode lay-hee hoo. Loud was the voice of the lonely goatherd: Lay-ee ode lay-ee ode-loo.

The children sing 'So Long, Farewell'
 

Embarrassed, confused, and slightly frightened, especially when the baroness comments on what
a lovely couple they make,
Maria beats a hasty retreat to her bedroom
to change clothes for dinner.

But the baroness follows her.

"There's nothing more irresistible to a man than a woman who's in love with him." The Baroness said.

The Reverend Mother responds by telling Maria that the love of a man and a woman is holy too, assuring her that if she loves the captain, it doesn't mean she loves God less. Ignoring Maria's pleas to remain at the abbey and be "safe," she sends her back to the Von Trapps to find out the true nature of her feelings for the captain and how God wants her to spend her love, inspiring her with one of the greatest songs of the film: "Climb Every Mountain."

"Maria, these walls were not built to shut out problems. You have to face them. You have to live the life you were born to live: Climb every mountain. Search high and low.

Taken aback, but convinced this development has answered her lingering questions, Maria informs the captain of her intention to stay only until arrangements can be made for another governess. But intrigued by his own unanswered questions about the reasons for her sudden departure without saying goodbye and subsequent return, the captain finds himself utterly distracted by her renewed presence.

In another expertly acted scene, Elsa at first seems impervious to the captain's captivation with Maria, yet upon realizing who really has the captain's heart, she swallows her hurt and disappointment and makes a gracious exit.

When Maria returns to the Von Trapps, the children are as excited to see her as she is to see them, but they have some news: the captain has announced his intention to marry the baroness.

"You can't marry someone when you're in love with someone else, can you?" --Captain von Trapp

Finally at liberty to confess her own feelings, Maria can't believe that after struggling so long to make a place for herself in life, she finds a place ready-made for her with the captain and his family:
 

"Perhaps I had a wicked childhood. Perhaps I had a miserable youth. But somewhere in my wicked, miserable past, there must have been a moment of truth. For here you are, standing there, loving me. Whether or not you should. So somewhere in my youth or childhood, I must have done something good."

And so they were married... Surrounded by hundreds of well-wishers as well as the children, Maria processes down the aisle of the cathedral at Mondsee in a simple, elegant Dorothy Jeakins gown with the Nonnberg Abbey nuns (never mind the geography) looking on approvingly.

The pealing of church bells is soon drowned out by the sound of goose-stepping boots on Salzburg's cobblestone streets however, as the political crisis that has been brewing throughout the film finally comes to a boil.

Instead, while Georg goes off by himself to read a telegram from Berlin, Maria counsels Liesl on the ups and downs of love. The young lad Rolfe, it seems, has been caught up in the political fervor of the Anschluss and is now occupied with more important matters than romantic summer strolls with Liesl. Considerably more poised, yet understanding as ever, Maria advises Liesl to cry a little and then wait for the sun to come out... as it always does

"When you're "sixteen going on seventeen," waiting for life to start, somebody kind who touches your mind will suddenly touch your heart..."

Maria's quiet moments as wife and mother are brief however, as Georg soberly returns with the telegram requesting his immediate acceptance of a commission in the German navy

With surprisingly little deliberation and no consultation with his wife, Georg tells Maria they must get out of Austria that very night. A few hours later, under the cover of darkness, Max reluctantly helps them quietly push the family car out of the driveway where Herr Zeller, the Nazi gauleiter, and his henchmen are waiting for them. In a quick cover-up, Captain von Trapp explains to Herr Zeller that the family is on its way to sing at the festival.

Incredulous, the gauleiter accepts this plausible explanation as a temporary delay in his orders and escorts the Von Trapps to the festival, after which he intends to take the captain to the naval base at Bremerhaven to accept his commission.

At the festival, held at an extraordinary outdoor concert hall called the Pelsenreitschule, or Rocky Riding School, the Von Trapps reprise such family favorites as "Do, a Deer" and "So Long, Farewell."

Then, in the culmination of the film's unity-through-music theme, Captain von Trapp takes the guitar and leads both his family and the audience in a love song which, in the intervening years, has often come to be confused for the national anthem of Austria, but was in truth, an original song written for THE SOUND OF MUSIC by Rodgers and Hammerstein -- "Edelweiss":

The national anthem of Austria during the 1930s was actually an imperial anthem entitled "Kaiserlied" which had been composed in the 18th century by Josef Haydn and carried forward into the post-World War I republic from the days of the Austro-Hungarian Empire. In 1922 however, the tune was adopted by Germany as the basis for its own anthem, "Lied der Deutschen," and retained throughout the Nazi regime of World War II.

Thus, with all the post-war confusion and political controversy still engendered by Europe's pre-war and wartime anthems, it is easy to understand why Rodgers and Hammerstein chose to write their own.

Escaping over the mountains