Thief of Time - Problem

'That is one of the great mysteries of the Way,' said Lu-Tze, nodding sagely. 'What chocolate do we
have left?'

'We're down to the nougat now,' said Unity. 'And I believe nougat is a terrible thing to cover with chocolate, where it can ambush the unsuspecting. Susan?'

Susan was peering up the street. 'Mmm?'

'Do you have any chocolate left?'

Susan shook her head. 'Mmm-mmm.'

'I believe you were carrying the cherry cremes?'

'Mmm?'

Susan swallowed, and then gave a cough that expressed, in a remarkably concise way, embarrassment  and annoyance.

'I just had one!' she snapped. 'I need the sugar.'

'I'm sure no one said you did have more than one,' said Unity meekly.

'We haven't been counting at all,' said Lu-Tze.

'If you have a handkerchief,' said Unity, still diplomatically, 'I could wipe away the chocolate around your mouth which must have inadvertently got there during the last engagement.'

Susan glared and used the back of her hand.

'It's just the sugar,' she said. 'That's all. It's fuel. And do stop going on about it! Look, we can't just let
you die to get-'

***

The Thief of Time - p315