The case in three lines. A friendly stranger offers Tara £300 for ten minutes' work: let £2,000 arrive in her account and send £1,700 on to his "supplier". The account turns out to be three weeks old, with borrowed photographs and the same message sent to three of her classmates. Her cousin has already done it twice, and he rings to ask if she's in.

One question to ask. "What should Tara say to her cousin?" Then: "Why would someone pay so much for so little?" Let them argue it through.

One thing to do at the table. Look at one real job advert together, such as a weekend shop job, and list what it tells you: who the employer is, what the work is, what it pays per hour. Then compare it with an offer that only needs your bank details.

The grown-up layer. The case is about money mules: people recruited, often online and often young, to move money from crime through their own bank accounts. It gives the cousin his strongest point, that money is tight and nothing has happened to him yet, and it gives the friendly recruiter his best manners, because real recruiters are friendly too. The habits it models are reading the offer aloud, tracing who sent it, pricing it per hour, and asking what the money is really paying for. If a young person has already been asked, or has already said yes, the safest next step is to tell their bank and a trusted adult straight away: telling early is always better than waiting.

The case leaves the line blank on purpose. Ask for it before you offer yours.