Write the plot for the episode of my kid's TV show "Tili and Wills" entitled "Snakes and Ladders".
Background on the show and characters: 
Willow: 6-year-old Great Dane, also known as Wills
Tilian: 3-month-old puppy, also known as Tili
Jessica: Willow and Tilian's human mother
Patrick: Willow and Tilian's human father
Jessica and Patrick brought home Tilian, a stray puppy they found on the streets. Their dog Willow is not used to sharing her parent's love and attention. She has largely been ignoring Tilian, seeing her as a nuisance and not wanting to interact with her. Tilian on the other hand, is desperate to befriend Willow and make her see the two of them can be best friends and sisters if only Willow would give her a chance.
Episode idea: This episode serves as a "turning point" for the series, as it is the episode where Willow changes her mind about Tilian and realizes the two of them can be friends and live together harmoniously. After being left alone at home, Tilian saves Willow from being bitten by a snake. The episode is entitled "Snakes and Ladders", so I would like there to also be a ladder incorporated into the story somehow. 
"Snakes and Ladders" 

It is a beautiful summer's day. Willow spends her morning eating breakfast, chewing on her bones, and watching cartoons on TV. Tilian tries to join in these activities with her, but other than a few irritated glances, Willow remains largely uninterested in spending time with her. Patrick and Jessica decide it is a good day to fix the broken tiles on the roof of their house, which was damaged in a storm a few days prior. 

As Jessica makes homemade dog treats in the kitchen, Patrick sets up his ladder and goes up to the roof to fix the tiles. Tilian and Willow also make their way into the backyard. Willow decides to take a nap under the shade of a tree, and Tilian chases butterflies and watches Patrick work on the roof. After fixing the tiles, Patrick begins his descent down the ladder. However, just as he's about to step off, he loses his balance and falls. His yelp startles Tilian and sends Jessica rushing to his aid. Willow on the other hand, barely rouses from her sleep. Patrick hurts his wrist in the fall and is worried it may be broken. Jessica decides the best course of action is to take him to the hospital, so the two of them hastily make their way there, leaving the dogs in the safety of the enclosed backyard. 

Worried about her Dad, Tilian tries to wake Willow, asking her questions about where they went and if he would be okay. Annoyed at being woken up, Willow gets up and moves to the other side of the yard to continue her nap. Feeling rejected, Tilian lays down on the other side of the yard and continues to watch butterflies. One of these butterflies lands on a bush next to where Willow is sleeping. At that moment, Tilian realizes there is a snake in the bush, and it's coming right for Willow! She races across the yard, barking furiously at the snake just as it is about to sink its teeth into Willow's leg. This scares the snake away and wakes Willow, who sees the snake slither away and realizes Tilian saved her from being bit. Upon their return, Jessica and Patrick are surprised to see Willow and Tilian playing in the backyard together and are delighted that the two of them have finally become friends.