The Mráz family is preparing for holidays. Parents are traveling to the spa and little Petr is going to the country to his grandparents. In addition, to the chaotic preparations, mother's friend is bringing a dog Blek. She wants Petr to look after it. Grandfather welcomes Petr and the dog with pleasure because he needs the ally against strict grandmother. Grandfather is not very skillful and thus grandmother often experiences troubles with his ideas.
| Actor | Role |
|---|---|
 Tomáš HolýPetr Mráz | Petr Mráz |
| BBohumil VávraGrandpa | Grandpa |
 Věra TichánkováGrandma | Grandma |
 Jiří HrzánDad | Dad |
 Hana MaciuchováMom | Mom |
 Oldřich NavrátilPlavec | Plavec |
 Naďa KonvalinkováPlavcová | Plavcová |
 Vladimír KratinaDrtikol | Drtikol |
| PPavel StránskýJarda | Jarda |
 Monika KvasničkováMilena | Milena |
| RRoman ŠmalclZdeněk | Zdeněk |
| JJakub HeglasJirka | Jirka |
 Jana BřežkováNot listed | Not listed |
| LLída BorovcováNot listed | Not listed |
| VValentin KryštofNot listed | Not listed |
 Helena RůžičkováNot listed | Not listed |
 Jitka MolavcováNot listed | Not listed |
 Vlastimil VenclíkNot listed | Not listed |
 Jarmila DerkováNot listed | Not listed |
| MMagda DolejšováNot listed | Not listed |
| JJindřich BílekNot listed | Not listed |
| MMarie HoláNot listed | Not listed |
| DDaniel NetušilNot listed | Not listed |
| BBarbora VošmikováNot listed | Not listed |
| VVladimír HrabánekDad (outdoor voice) | Dad (outdoor voice) |
 Miriam ChytilováMilena (voice) | Milena (voice) |
| DDavid StrupekJirka (voice) | Jirka (voice) |