“The past is never where you think you left it.”
— Katherine Anne Porter

Reviews for Penumbra

Penumbra is an engrossing thriller with twists and a dramatic ending that hints at more to come. I do hope there is more....
— Ben Cameron, Publicity Review
Mature ... a great first novel, Mumford-Yeo clearly has a gift
— Connor Vickery, Kindle Publishing Review
A cinematic thriller about family secrets and a seemingly perfect couple
— Publicity Reviewer
An absolute page-turner! Mumford-Yeo managed to capture her audience with clever, witty and intelligent writing that will make you unable to stop reading. Beautifully scenic, captivating and unpredictable. A much needed breath of fresh air in thriller literature - Mumford-Yeo is one to watch!
— Amazon Customer
Well, this was one thoroughly enjoyable read! I found the author’s language and intelligent constructs a fresh departure from the usual banter churned out in your average novel in this genre and I have seen my fair share. The depth she goes to in the portrait of her characters draws you into the story and as it unfolds you realise there are deeper and darker layers with a satisfying ending that does not disappoint. It looks like this is a first publication from the author and I’m sure we’ll be treated to others.
— Amazon Reviewer
What a fabulous debut novel. Set mainly in contemporary London, Mumford-Yeo’s pacy thriller entertained right through to the final chapter. The characters were fleshed out and the plot line contained elements of how easily modern lives can be enveigled. Whether curled up on the sofa or stretched out on the beach, Penumbra is certainly a riveting read.
— Good Reads Reviewer
Fantastically creepy. I’m half-way through this and struggling to put it down
— Good Reads Reviewer
Great read - loved every moment
— Kindle customer

Available to buy now at Waterstones, Amazon, Barns & Noble, Foyles bookstore, iBooks and selected retailers.



1. The partially shaded outer region of the shadow cast by an

opaque object.

2. A peripheral or indeterminate area or group.

"an immense penumbra of theory surrounds any observation"


To the outside world, Bella Strukome has the perfect urbane life. Beautiful, talented and with a devoted husband, she is the envy of people she's never even met. But the tragedy that decimated her thirteen years ago still casts a shadow.

It’s the middle of a stifling London summer when insidious events begin to puncture Nick and Bella’s seamless existence. They must face a nebulous enemy - someone that knows everything about their lives and appears to be one step ahead - testing their relationship to its limits.

Penumbra is a dark urban thriller, deconstructing the veneer of perfect family life - revealing dark secrets, hidden lives and the brutal ends someone will go to reclaiming their lost years.


Author Bio

Heidi Mumford - Yeo is a British actress who has appeared in film, television and the West End. Penumbra is her debut novel. She has also written a series of children’s books ‘The Adventures of Freddy.’

She graduated in Law from Durham University, before training as an actress in London. Heidi is a passionate proponent of Animal Rights and campaigns across a raft of issues, working alongside various charities.

 Heidi lives in London with her husband and two dogs, Indiana Jones and Freddy.