Cloud Filly is an exciting and adventurous fantasy story about two teenage siblings, Drake and Nellie, who magically escape their impoverished dreary lives through a mystical portal.  The portal transports them to the enchanting paradise of Uni where they discover talking unicorns that fly, sorceresses, and other delightful creatures. Written by a teenager for "tween" readers, Cloud Filly is a fast paced read, heavily illustrated with beautiful drawings.  The author uses several unique points of view to allow the reader to get into the mind of the humans and unicorns.  She allows us to feel what they are feeling and why. 

At the outset of the novel, Drake and Nellie live in the "real world," where they can only dream of owning horses.  They both dream of some day becoming professional jockeys and are passionate about horses.  But sadly, they worry that they will never be able to afford lessons or even pay to watch a race from inside the track.  They can only watch the thunderous excitement of horse racing by climbing a tree just outside of the racetrack gates.

Drake and Nellie are enjoying the view of a horse race, high in their tree top perch, when suddenly one of them happens upon a strange portal hidden within the tree.  Abruptly the two find themselves no longer in the tree watching the races, but are instead in a new world.  They are quickly greeted by two young sorceresses who take them under their wing and teach them the ways of Uni.  To their amazement, Drake and Nellie find that there are unicorns in Uni, hence the name.  And not only that; the unicorns can talk and have magical powers.  The sorceress's sweet unicorn, Alidar, teaches the new comers all about the many types of unicorns that can be found there. 

Drake is excited by the prospects of racing in this new land.  He decides he wants to catch a steed of his own and make a living racing.  In his search for the perfect unicorn, he finds a beautiful white young filly running free through the prairies.  He learns that she is a cloud unicorn from a herd that lives in the clouds.  She loves to gallop on the ground through the lush green plains and is very independent, feisty and quite unapproachable.  The cloud unicorn's name is Cloudberry.  Because of her outgoing nature, she is curious about Drake's advances and allows him to befriend her.  Drake is ecstatic and begins to gently form a relationship with her.  He learns to ride her and has quite the time introducing her to saddles and bits.  She eventually takes him flying and introduces him to her herd in the clouds.  Cloudberry shows Drake some of the peculiarities of her world including cloud berries and the curious colorful dots on her coat when exposed to rain but vanish as soon as she is dry.  They learn how to race together and manage to win money in several amateur races.  Drake uses his winnings to buy a new saddle and tack and pay for board at the sorceress sister’s barn.

But there is a dark horse on the horizon in Uni; an evil stallion lurking about named Nightcloud.  He is Cloudberry's sinister brother.  Throughout the novel, Cloudberry has several violent confrontations with him but no one knows why he hates her or why he so fiercely wants to harm her.  He insists that he is out for revenge but for what?  

It is later revealed that he was the colt and first born of Cloudberry's mother, Mamatus.  He lived in the clouds with his family until one day he accidentally fell off the clouds, crashing to earth.  Somehow he survived.  Mamatus did not fly down to get him because she was expecting his father, Galaxy Dancer, to retrieve him and train him as the next gate keeper.  Being the gate keeper is very difficult, dangerous and lonely because you must protect the portals in outside dimensions from improper visitors.  However, Galaxy Dancer never came for him.   Nightcloud blamed his lost ideal childhood on Cloudberry, his younger sibling, since she was getting all of the attention from her mother and he was forgotten down on earth.
 
Everyone exposed to Nightcloud's evil arrogant ways are convinced he is crazy and has no hope of recovery.  Everyone except Lorelei, one of the sorceresses who have taken the teens under her wing.  She seems to know what is going on with Nightcloud and is quietly monitoring the events occurring to the teens.  Lorelei is a healer by profession and the magical creatures in the area that are hurt or sick come to her for help with potions and therapy.

Over time, Nellie sees how content Drake is with Cloudberry so she wants her own unicorn friend.  She is confident that she can race as well as Drake and with the right horse even better.  Nellie considers several prospects, but there is just something about the sight of the incredibly beautiful and strong Nightcloud that won't leave her mind.  Yet, it is such a dangerous prospect that she keeps the fantasy of Nightcloud to herself.

Drake and Cloudberry manage to win a very important race and everyone is very happy about the future prospects.  The siblings and the filly take off on a ride towards the sea just to relax and bask in their success and wonderful new life.  But their celebration is soon interrupted by a visit from Nightcloud.  He wants to kill Cloudberry.  A climactic and intense fight ensues between Cloudberry and her brother and eventually he tries to push her over a cliff into the ocean.  A huge storm comes up with driving rain and lightning during the dramatic fight.  He finally manages to push her off but she takes him with her.  As they fall, they hit several rocks and they end up in the rough ocean.  Cloudberry takes pity on the unconscious Nightcloud and drags him to the beach and leaves him there, his horn now broken from the fall.  The three are horrified about the confrontation and Nellie is heartbroken to see Nightcloud in such a way.  Drake, Nellie, and Cloudberry head back to their Uni home and begin to calm down.  They are proud of their defeat of Nightcloud, as well as knowing the great future that lay ahead in the racing world. 

However, Nellie still cannot get the vision of the great stallion out of her mind and continues to dream of one day having him as her own.  The sequel, Sky Stallion, picks up with the relationship that develops under secrecy between Nellie and the stallion.