That afternoon when Jack gets home, he runs straight over to Billie’s house.

She is still in bed.

She looks very lonely and very bored.

‘I had the best party, Billie!’ he says happily.

He bounces up and down on her bed.

‘The play centre was amazing. You should have seen the ball pit!

We had so much fun.

And everyone loved the birthday cake.’

Billie smiles. ‘Did you save me some?’

‘Oh,’ says Jack. ‘I forgot!’

‘What about a lolly bag?’ Billie asks.

Jack feels his cheeks get hot. ‘Sorry,’ he says. ‘Benny took the last one.’

‘What about the presents?’ Billie says.

‘Did you wait for me to open them?’

Jack bites his lip and shakes his head. ‘No.

I opened them already.’

Billie frowns. She pulls her blanket up to her chin. ‘You didn’t miss me at all! You didn’t save me one thing!’

Jack feels hurt that Billie is so cross with him.

‘Well, it’s not my fault!’ he says. ‘You didn’t come to my party!’

‘I couldn’t, could I?’ Billie shouts. ‘I was sick!’

‘Well you don’t have to shout at me!’ Jack says.

He storms out of Billie’s room.

Then he stomps all the way home.

By the time he is back in his bedroom, Jack already feels bad.

Billie is right, he thinks. I did forget her. I was having such a good time that I forgot my best friend!

Jack tries to think of something that will make Billie feel better.

He looks over at his box of Lego. Suddenly he has an idea. He tips all the coloured pieces onto his desk. Then he begins to build.

He builds ladders and slides and climbing frames. He even builds a ball pit with tiny coloured balls.

It takes him a long time. But Jack is happy with his work.

It looks just like the play centre.

Last of all, he chooses lots of tiny Lego characters. They will be all the people in his class.

And this time he is very careful not to forget Billie.