 When burglaries are reported in the neighborhood, an alarm system is required- to keep it cheap, student Koen and handyman Odilon create, install and test one themselves. Now her latest flame teaches classes in first aid (EHBO is the Dutch abbreviation, hence he title) Betty suddenly develops a  social conscience  that dictates they must have one in the house. But when he cancels, the others don t tell about that call so they can turn the whole thing into a farce of excessive bandaging and CPR.